* [RFC][PATCH 01/23 v4] tracing: Fix trace_seq_bitmask() to start at current position
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return() Steven Rostedt
` (21 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0001-tracing-Fix-trace_seq_bitmask-to-start-at-current-po.patch --]
[-- Type: text/plain, Size: 1068 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
In trace_seq_bitmask() it calls bitmap_scnprintf() not from the current
position of the trace_seq buffer (s->buffer + s->len), but instead from
the beginning of the buffer (s->buffer).
Luckily, the only user of this "ipi_raise tracepoint" uses it as the
first parameter, and as such, the start of the temp buffer in
include/trace/ftrace.h (see __get_bitmask()).
Reported-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_seq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 1f24ed99dca2..b100994a17fe 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -122,7 +122,7 @@ int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
if (s->full || !len)
return 0;
- ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+ ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
s->len += ret;
return 1;
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return()
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 01/23 v4] tracing: Fix trace_seq_bitmask() to start at current position Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 11:25 ` Petr Mladek
2014-11-14 1:12 ` [RFC][PATCH 03/23 v4] blktrace/tracing: Use trace_seq_has_overflowed() helper function Steven Rostedt
` (20 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0002-tracing-Add-trace_seq_has_overflowed-and-trace_handl.patch --]
[-- Type: text/plain, Size: 29383 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Adding a trace_seq_has_overflowed() which returns true if the trace_seq
had too much written into it allows us to simplify the code.
Instead of checking the return value of every call to trace_seq_printf()
and friends, they can all be called normally, and at the end we can
return !trace_seq_has_overflowed() instead.
Several functions also return TRACE_TYPE_PARTIAL_LINE when the trace_seq
overflowed and TRACE_TYPE_HANDLED otherwise. Another helper function
was created called trace_handle_return() which takes a trace_seq and
returns these enums. Using this helper function also simplifies the
code.
This change also makes it possible to remove the return values of
trace_seq_printf() and friends. They should instead just be
void functions.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/ftrace_event.h | 11 ++
include/linux/trace_seq.h | 12 ++
include/trace/ftrace.h | 6 +-
kernel/trace/trace.c | 69 +++----
kernel/trace/trace.h | 1 +
kernel/trace/trace_output.c | 416 +++++++++++++++++--------------------------
kernel/trace/trace_output.h | 16 +-
7 files changed, 231 insertions(+), 300 deletions(-)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 28672e87e910..0bebb5c348b8 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -138,6 +138,17 @@ enum print_line_t {
TRACE_TYPE_NO_CONSUME = 3 /* Handled but ask to not consume */
};
+/*
+ * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
+ * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
+ * simplifies those functions and keeps them in sync.
+ */
+static inline enum print_line_t trace_handle_return(struct trace_seq *s)
+{
+ return trace_seq_has_overflowed(s) ?
+ TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
+}
+
void tracing_generic_entry_update(struct trace_entry *entry,
unsigned long flags,
int pc);
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index ea6c9dea79e3..07eda413dfcf 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -40,6 +40,18 @@ trace_seq_buffer_ptr(struct trace_seq *s)
return s->buffer + s->len;
}
+/**
+ * trace_seq_has_overflowed - return true if the trace_seq took too much
+ * @s: trace sequence descriptor
+ *
+ * Returns true if too much data was added to the trace_seq and it is
+ * now full and will not take anymore.
+ */
+static inline bool trace_seq_has_overflowed(struct trace_seq *s)
+{
+ return s->full || s->len > PAGE_SIZE - 1;
+}
+
/*
* Currently only defined when tracing is enabled.
*/
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 26b4f2e13275..f13471b5d27a 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -280,11 +280,9 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags, \
if (ret) \
return ret; \
\
- ret = trace_seq_printf(s, print); \
- if (!ret) \
- return TRACE_TYPE_PARTIAL_LINE; \
+ trace_seq_printf(s, print); \
\
- return TRACE_TYPE_HANDLED; \
+ return trace_handle_return(s); \
} \
static struct trace_event_functions ftrace_event_type_funcs_##call = { \
.trace = ftrace_raw_output_##call, \
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8a528392b1f4..f5a435a6e8fb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2648,24 +2648,21 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
event = ftrace_find_event(entry->type);
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
- if (!trace_print_lat_context(iter))
- goto partial;
- } else {
- if (!trace_print_context(iter))
- goto partial;
- }
+ if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+ trace_print_lat_context(iter);
+ else
+ trace_print_context(iter);
}
+ if (trace_seq_has_overflowed(s))
+ return TRACE_TYPE_PARTIAL_LINE;
+
if (event)
return event->funcs->trace(iter, sym_flags, event);
- if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
- goto partial;
+ trace_seq_printf(s, "Unknown type %d\n", entry->type);
- return TRACE_TYPE_HANDLED;
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
@@ -2676,22 +2673,20 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
entry = iter->ent;
- if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- if (!trace_seq_printf(s, "%d %d %llu ",
- entry->pid, iter->cpu, iter->ts))
- goto partial;
- }
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO)
+ trace_seq_printf(s, "%d %d %llu ",
+ entry->pid, iter->cpu, iter->ts);
+
+ if (trace_seq_has_overflowed(s))
+ return TRACE_TYPE_PARTIAL_LINE;
event = ftrace_find_event(entry->type);
if (event)
return event->funcs->raw(iter, 0, event);
- if (!trace_seq_printf(s, "%d ?\n", entry->type))
- goto partial;
+ trace_seq_printf(s, "%d ?\n", entry->type);
- return TRACE_TYPE_HANDLED;
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
@@ -2704,9 +2699,11 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
entry = iter->ent;
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
- SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
- SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+ SEQ_PUT_HEX_FIELD(s, entry->pid);
+ SEQ_PUT_HEX_FIELD(s, iter->cpu);
+ SEQ_PUT_HEX_FIELD(s, iter->ts);
+ if (trace_seq_has_overflowed(s))
+ return TRACE_TYPE_PARTIAL_LINE;
}
event = ftrace_find_event(entry->type);
@@ -2716,9 +2713,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
return ret;
}
- SEQ_PUT_FIELD_RET(s, newline);
+ SEQ_PUT_FIELD(s, newline);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
@@ -2730,9 +2727,11 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
entry = iter->ent;
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- SEQ_PUT_FIELD_RET(s, entry->pid);
- SEQ_PUT_FIELD_RET(s, iter->cpu);
- SEQ_PUT_FIELD_RET(s, iter->ts);
+ SEQ_PUT_FIELD(s, entry->pid);
+ SEQ_PUT_FIELD(s, iter->cpu);
+ SEQ_PUT_FIELD(s, iter->ts);
+ if (trace_seq_has_overflowed(s))
+ return TRACE_TYPE_PARTIAL_LINE;
}
event = ftrace_find_event(entry->type);
@@ -2778,10 +2777,12 @@ enum print_line_t print_trace_line(struct trace_iterator *iter)
{
enum print_line_t ret;
- if (iter->lost_events &&
- !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
- iter->cpu, iter->lost_events))
- return TRACE_TYPE_PARTIAL_LINE;
+ if (iter->lost_events) {
+ trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+ iter->cpu, iter->lost_events);
+ if (trace_seq_has_overflowed(&iter->seq))
+ return TRACE_TYPE_PARTIAL_LINE;
+ }
if (iter->trace && iter->trace->print_line) {
ret = iter->trace->print_line(iter);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3376de623ea0..19418221b302 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -14,6 +14,7 @@
#include <linux/trace_seq.h>
#include <linux/ftrace_event.h>
#include <linux/compiler.h>
+#include <linux/trace_seq.h>
#ifdef CONFIG_FTRACE_SYSCALLS
#include <asm/unistd.h> /* For NR_SYSCALLS */
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index cfa91de22e27..163c11b6b8ff 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -25,15 +25,12 @@ enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
struct bputs_entry *field;
- int ret;
trace_assign_type(field, entry);
- ret = trace_seq_puts(s, field->str);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, field->str);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
@@ -41,15 +38,12 @@ enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
struct bprint_entry *field;
- int ret;
trace_assign_type(field, entry);
- ret = trace_seq_bprintf(s, field->fmt, field->buf);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_bprintf(s, field->fmt, field->buf);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
@@ -57,15 +51,12 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
struct print_entry *field;
- int ret;
trace_assign_type(field, entry);
- ret = trace_seq_puts(s, field->buf);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, field->buf);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
const char *
@@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
struct trace_seq *s = &iter->seq;
struct trace_seq *p = &iter->tmp_seq;
struct trace_entry *entry;
- int ret;
event = container_of(trace_event, struct ftrace_event_call, event);
entry = iter->ent;
@@ -204,8 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
}
trace_seq_init(p);
- ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
- if (!ret)
+ trace_seq_printf(s, "%s: ", ftrace_event_name(event));
+
+ if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
return 0;
@@ -216,18 +207,11 @@ static int ftrace_output_raw(struct trace_iterator *iter, char *name,
char *fmt, va_list ap)
{
struct trace_seq *s = &iter->seq;
- int ret;
- ret = trace_seq_printf(s, "%s: ", name);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = trace_seq_vprintf(s, fmt, ap);
+ trace_seq_printf(s, "%s: ", name);
+ trace_seq_vprintf(s, fmt, ap);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
@@ -260,7 +244,7 @@ static inline const char *kretprobed(const char *name)
}
#endif /* CONFIG_KRETPROBES */
-static int
+static void
seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
{
#ifdef CONFIG_KALLSYMS
@@ -271,12 +255,11 @@ seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
name = kretprobed(str);
- return trace_seq_printf(s, fmt, name);
+ trace_seq_printf(s, fmt, name);
#endif
- return 1;
}
-static int
+static void
seq_print_sym_offset(struct trace_seq *s, const char *fmt,
unsigned long address)
{
@@ -287,9 +270,8 @@ seq_print_sym_offset(struct trace_seq *s, const char *fmt,
sprint_symbol(str, address);
name = kretprobed(str);
- return trace_seq_printf(s, fmt, name);
+ trace_seq_printf(s, fmt, name);
#endif
- return 1;
}
#ifndef CONFIG_64BIT
@@ -320,14 +302,14 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
if (file) {
ret = trace_seq_path(s, &file->f_path);
if (ret)
- ret = trace_seq_printf(s, "[+0x%lx]",
- ip - vmstart);
+ trace_seq_printf(s, "[+0x%lx]",
+ ip - vmstart);
}
up_read(&mm->mmap_sem);
}
if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
- ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
- return ret;
+ trace_seq_printf(s, " <" IP_FMT ">", ip);
+ return !trace_seq_has_overflowed(s);
}
int
@@ -335,7 +317,6 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
unsigned long sym_flags)
{
struct mm_struct *mm = NULL;
- int ret = 1;
unsigned int i;
if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
@@ -354,48 +335,45 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
unsigned long ip = entry->caller[i];
- if (ip == ULONG_MAX || !ret)
+ if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
break;
- if (ret)
- ret = trace_seq_puts(s, " => ");
+
+ trace_seq_puts(s, " => ");
+
if (!ip) {
- if (ret)
- ret = trace_seq_puts(s, "??");
- if (ret)
- ret = trace_seq_putc(s, '\n');
+ trace_seq_puts(s, "??");
+ trace_seq_putc(s, '\n');
continue;
}
- if (!ret)
- break;
- if (ret)
- ret = seq_print_user_ip(s, mm, ip, sym_flags);
- ret = trace_seq_putc(s, '\n');
+
+ seq_print_user_ip(s, mm, ip, sym_flags);
+ trace_seq_putc(s, '\n');
}
if (mm)
mmput(mm);
- return ret;
+
+ return !trace_seq_has_overflowed(s);
}
int
seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
{
- int ret;
-
- if (!ip)
- return trace_seq_putc(s, '0');
+ if (!ip) {
+ trace_seq_putc(s, '0');
+ goto out;
+ }
if (sym_flags & TRACE_ITER_SYM_OFFSET)
- ret = seq_print_sym_offset(s, "%s", ip);
+ seq_print_sym_offset(s, "%s", ip);
else
- ret = seq_print_sym_short(s, "%s", ip);
-
- if (!ret)
- return 0;
+ seq_print_sym_short(s, "%s", ip);
if (sym_flags & TRACE_ITER_SYM_ADDR)
- ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
- return ret;
+ trace_seq_printf(s, " <" IP_FMT ">", ip);
+
+ out:
+ return !trace_seq_has_overflowed(s);
}
/**
@@ -413,7 +391,6 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
char irqs_off;
int hardirq;
int softirq;
- int ret;
hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
@@ -445,16 +422,15 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
softirq ? 's' :
'.';
- if (!trace_seq_printf(s, "%c%c%c",
- irqs_off, need_resched, hardsoft_irq))
- return 0;
+ trace_seq_printf(s, "%c%c%c",
+ irqs_off, need_resched, hardsoft_irq);
if (entry->preempt_count)
- ret = trace_seq_printf(s, "%x", entry->preempt_count);
+ trace_seq_printf(s, "%x", entry->preempt_count);
else
- ret = trace_seq_putc(s, '.');
+ trace_seq_putc(s, '.');
- return ret;
+ return !trace_seq_has_overflowed(s);
}
static int
@@ -464,9 +440,8 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
trace_find_cmdline(entry->pid, comm);
- if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
- comm, entry->pid, cpu))
- return 0;
+ trace_seq_printf(s, "%8.8s-%-5d %3d",
+ comm, entry->pid, cpu);
return trace_print_lat_fmt(s, entry);
}
@@ -493,24 +468,29 @@ lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
unsigned long rel_msec = (unsigned long)rel_ts;
- return trace_seq_printf(
- s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
- ns2usecs(iter->ts),
- abs_msec, abs_usec,
- rel_msec, rel_usec);
+ trace_seq_printf(
+ s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
+ ns2usecs(iter->ts),
+ abs_msec, abs_usec,
+ rel_msec, rel_usec);
+
} else if (verbose && !in_ns) {
- return trace_seq_printf(
- s, "[%016llx] %lld (+%lld): ",
- iter->ts, abs_ts, rel_ts);
+ trace_seq_printf(
+ s, "[%016llx] %lld (+%lld): ",
+ iter->ts, abs_ts, rel_ts);
+
} else if (!verbose && in_ns) {
- return trace_seq_printf(
- s, " %4lldus%c: ",
- abs_ts,
- rel_ts > preempt_mark_thresh_us ? '!' :
- rel_ts > 1 ? '+' : ' ');
+ trace_seq_printf(
+ s, " %4lldus%c: ",
+ abs_ts,
+ rel_ts > preempt_mark_thresh_us ? '!' :
+ rel_ts > 1 ? '+' : ' ');
+
} else { /* !verbose && !in_ns */
- return trace_seq_printf(s, " %4lld: ", abs_ts);
+ trace_seq_printf(s, " %4lld: ", abs_ts);
}
+
+ return !trace_seq_has_overflowed(s);
}
int trace_print_context(struct trace_iterator *iter)
@@ -520,34 +500,29 @@ int trace_print_context(struct trace_iterator *iter)
unsigned long long t;
unsigned long secs, usec_rem;
char comm[TASK_COMM_LEN];
- int ret;
trace_find_cmdline(entry->pid, comm);
- ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
+ trace_seq_printf(s, "%16s-%-5d [%03d] ",
comm, entry->pid, iter->cpu);
- if (!ret)
- return 0;
- if (trace_flags & TRACE_ITER_IRQ_INFO) {
- ret = trace_print_lat_fmt(s, entry);
- if (!ret)
- return 0;
- }
+ if (trace_flags & TRACE_ITER_IRQ_INFO)
+ trace_print_lat_fmt(s, entry);
if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
t = ns2usecs(iter->ts);
usec_rem = do_div(t, USEC_PER_SEC);
secs = (unsigned long)t;
- return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
+ trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
} else
- return trace_seq_printf(s, " %12llu: ", iter->ts);
+ trace_seq_printf(s, " %12llu: ", iter->ts);
+
+ return !trace_seq_has_overflowed(s);
}
int trace_print_lat_context(struct trace_iterator *iter)
{
u64 next_ts;
- int ret;
/* trace_find_next_entry will reset ent_size */
int ent_size = iter->ent_size;
struct trace_seq *s = &iter->seq;
@@ -567,18 +542,17 @@ int trace_print_lat_context(struct trace_iterator *iter)
trace_find_cmdline(entry->pid, comm);
- ret = trace_seq_printf(
- s, "%16s %5d %3d %d %08x %08lx ",
- comm, entry->pid, iter->cpu, entry->flags,
- entry->preempt_count, iter->idx);
+ trace_seq_printf(
+ s, "%16s %5d %3d %d %08x %08lx ",
+ comm, entry->pid, iter->cpu, entry->flags,
+ entry->preempt_count, iter->idx);
} else {
- ret = lat_print_generic(s, entry, iter->cpu);
+ lat_print_generic(s, entry, iter->cpu);
}
- if (ret)
- ret = lat_print_timestamp(iter, next_ts);
+ lat_print_timestamp(iter, next_ts);
- return ret;
+ return !trace_seq_has_overflowed(s);
}
static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
@@ -764,10 +738,9 @@ EXPORT_SYMBOL_GPL(unregister_ftrace_event);
enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
struct trace_event *event)
{
- if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(&iter->seq);
}
/* TRACE_FN */
@@ -779,24 +752,16 @@ static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- if (!seq_print_ip_sym(s, field->ip, flags))
- goto partial;
+ seq_print_ip_sym(s, field->ip, flags);
if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
- if (!trace_seq_puts(s, " <-"))
- goto partial;
- if (!seq_print_ip_sym(s,
- field->parent_ip,
- flags))
- goto partial;
+ trace_seq_puts(s, " <-");
+ seq_print_ip_sym(s, field->parent_ip, flags);
}
- if (!trace_seq_putc(s, '\n'))
- goto partial;
- return TRACE_TYPE_HANDLED;
+ trace_seq_putc(s, '\n');
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
@@ -806,12 +771,11 @@ static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
- field->ip,
- field->parent_ip))
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(&iter->seq, "%lx %lx\n",
+ field->ip,
+ field->parent_ip);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(&iter->seq);
}
static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
@@ -822,10 +786,10 @@ static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- SEQ_PUT_HEX_FIELD_RET(s, field->ip);
- SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
+ SEQ_PUT_HEX_FIELD(s, field->ip);
+ SEQ_PUT_HEX_FIELD(s, field->parent_ip);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
@@ -836,10 +800,10 @@ static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- SEQ_PUT_FIELD_RET(s, field->ip);
- SEQ_PUT_FIELD_RET(s, field->parent_ip);
+ SEQ_PUT_FIELD(s, field->ip);
+ SEQ_PUT_FIELD(s, field->parent_ip);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_fn_funcs = {
@@ -868,18 +832,17 @@ static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
T = task_state_char(field->next_state);
S = task_state_char(field->prev_state);
trace_find_cmdline(field->next_pid, comm);
- if (!trace_seq_printf(&iter->seq,
- " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
- field->prev_pid,
- field->prev_prio,
- S, delim,
- field->next_cpu,
- field->next_pid,
- field->next_prio,
- T, comm))
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_printf(&iter->seq,
+ " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
+ field->prev_pid,
+ field->prev_prio,
+ S, delim,
+ field->next_cpu,
+ field->next_pid,
+ field->next_prio,
+ T, comm);
+
+ return trace_handle_return(&iter->seq);
}
static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
@@ -904,17 +867,16 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
if (!S)
S = task_state_char(field->prev_state);
T = task_state_char(field->next_state);
- if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
- field->prev_pid,
- field->prev_prio,
- S,
- field->next_cpu,
- field->next_pid,
- field->next_prio,
- T))
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
+ field->prev_pid,
+ field->prev_prio,
+ S,
+ field->next_cpu,
+ field->next_pid,
+ field->next_prio,
+ T);
+
+ return trace_handle_return(&iter->seq);
}
static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
@@ -942,15 +904,15 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
S = task_state_char(field->prev_state);
T = task_state_char(field->next_state);
- SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
- SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
- SEQ_PUT_HEX_FIELD_RET(s, S);
- SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
- SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
- SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
- SEQ_PUT_HEX_FIELD_RET(s, T);
+ SEQ_PUT_HEX_FIELD(s, field->prev_pid);
+ SEQ_PUT_HEX_FIELD(s, field->prev_prio);
+ SEQ_PUT_HEX_FIELD(s, S);
+ SEQ_PUT_HEX_FIELD(s, field->next_cpu);
+ SEQ_PUT_HEX_FIELD(s, field->next_pid);
+ SEQ_PUT_HEX_FIELD(s, field->next_prio);
+ SEQ_PUT_HEX_FIELD(s, T);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
@@ -973,15 +935,15 @@ static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
trace_assign_type(field, iter->ent);
- SEQ_PUT_FIELD_RET(s, field->prev_pid);
- SEQ_PUT_FIELD_RET(s, field->prev_prio);
- SEQ_PUT_FIELD_RET(s, field->prev_state);
- SEQ_PUT_FIELD_RET(s, field->next_cpu);
- SEQ_PUT_FIELD_RET(s, field->next_pid);
- SEQ_PUT_FIELD_RET(s, field->next_prio);
- SEQ_PUT_FIELD_RET(s, field->next_state);
+ SEQ_PUT_FIELD(s, field->prev_pid);
+ SEQ_PUT_FIELD(s, field->prev_prio);
+ SEQ_PUT_FIELD(s, field->prev_state);
+ SEQ_PUT_FIELD(s, field->next_cpu);
+ SEQ_PUT_FIELD(s, field->next_pid);
+ SEQ_PUT_FIELD(s, field->next_prio);
+ SEQ_PUT_FIELD(s, field->next_state);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_ctx_funcs = {
@@ -1021,23 +983,19 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
trace_assign_type(field, iter->ent);
end = (unsigned long *)((long)iter->ent + iter->ent_size);
- if (!trace_seq_puts(s, "<stack trace>\n"))
- goto partial;
+ trace_seq_puts(s, "<stack trace>\n");
for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
- if (!trace_seq_puts(s, " => "))
- goto partial;
- if (!seq_print_ip_sym(s, *p, flags))
- goto partial;
- if (!trace_seq_putc(s, '\n'))
- goto partial;
- }
+ if (trace_seq_has_overflowed(s))
+ break;
- return TRACE_TYPE_HANDLED;
+ trace_seq_puts(s, " => ");
+ seq_print_ip_sym(s, *p, flags);
+ trace_seq_putc(s, '\n');
+ }
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_stack_funcs = {
@@ -1058,16 +1016,10 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
trace_assign_type(field, iter->ent);
- if (!trace_seq_puts(s, "<user stack trace>\n"))
- goto partial;
-
- if (!seq_print_userip_objs(field, s, flags))
- goto partial;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_puts(s, "<user stack trace>\n");
+ seq_print_userip_objs(field, s, flags);
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_user_stack_funcs = {
@@ -1090,19 +1042,11 @@ trace_bputs_print(struct trace_iterator *iter, int flags,
trace_assign_type(field, entry);
- if (!seq_print_ip_sym(s, field->ip, flags))
- goto partial;
+ seq_print_ip_sym(s, field->ip, flags);
+ trace_seq_puts(s, ": ");
+ trace_seq_puts(s, field->str);
- if (!trace_seq_puts(s, ": "))
- goto partial;
-
- if (!trace_seq_puts(s, field->str))
- goto partial;
-
- return TRACE_TYPE_HANDLED;
-
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
@@ -1115,16 +1059,10 @@ trace_bputs_raw(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- if (!trace_seq_printf(s, ": %lx : ", field->ip))
- goto partial;
-
- if (!trace_seq_puts(s, field->str))
- goto partial;
+ trace_seq_printf(s, ": %lx : ", field->ip);
+ trace_seq_puts(s, field->str);
- return TRACE_TYPE_HANDLED;
-
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_bputs_funcs = {
@@ -1148,19 +1086,11 @@ trace_bprint_print(struct trace_iterator *iter, int flags,
trace_assign_type(field, entry);
- if (!seq_print_ip_sym(s, field->ip, flags))
- goto partial;
-
- if (!trace_seq_puts(s, ": "))
- goto partial;
-
- if (!trace_seq_bprintf(s, field->fmt, field->buf))
- goto partial;
+ seq_print_ip_sym(s, field->ip, flags);
+ trace_seq_puts(s, ": ");
+ trace_seq_bprintf(s, field->fmt, field->buf);
- return TRACE_TYPE_HANDLED;
-
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
@@ -1173,16 +1103,10 @@ trace_bprint_raw(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- if (!trace_seq_printf(s, ": %lx : ", field->ip))
- goto partial;
-
- if (!trace_seq_bprintf(s, field->fmt, field->buf))
- goto partial;
+ trace_seq_printf(s, ": %lx : ", field->ip);
+ trace_seq_bprintf(s, field->fmt, field->buf);
- return TRACE_TYPE_HANDLED;
-
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static struct trace_event_functions trace_bprint_funcs = {
@@ -1204,16 +1128,10 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
trace_assign_type(field, iter->ent);
- if (!seq_print_ip_sym(s, field->ip, flags))
- goto partial;
-
- if (!trace_seq_printf(s, ": %s", field->buf))
- goto partial;
+ seq_print_ip_sym(s, field->ip, flags);
+ trace_seq_printf(s, ": %s", field->buf);
- return TRACE_TYPE_HANDLED;
-
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
@@ -1223,13 +1141,9 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
trace_assign_type(field, iter->ent);
- if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
- goto partial;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
- partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(&iter->seq);
}
static struct trace_event_functions trace_print_funcs = {
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 80b25b585a70..8ef2c40efb3c 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -35,17 +35,11 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
extern int __unregister_ftrace_event(struct trace_event *event);
extern struct rw_semaphore trace_event_sem;
-#define SEQ_PUT_FIELD_RET(s, x) \
-do { \
- if (!trace_seq_putmem(s, &(x), sizeof(x))) \
- return TRACE_TYPE_PARTIAL_LINE; \
-} while (0)
-
-#define SEQ_PUT_HEX_FIELD_RET(s, x) \
-do { \
- if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
- return TRACE_TYPE_PARTIAL_LINE; \
-} while (0)
+#define SEQ_PUT_FIELD(s, x) \
+ trace_seq_putmem(s, &(x), sizeof(x))
+
+#define SEQ_PUT_HEX_FIELD(s, x) \
+ trace_seq_putmem_hex(s, &(x), sizeof(x))
#endif
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return()
2014-11-14 1:12 ` [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return() Steven Rostedt
@ 2014-11-14 11:25 ` Petr Mladek
2014-11-14 11:58 ` Steven Rostedt
2014-11-14 18:21 ` Steven Rostedt
0 siblings, 2 replies; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 11:25 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:12:46, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Adding a trace_seq_has_overflowed() which returns true if the trace_seq
> had too much written into it allows us to simplify the code.
>
> Instead of checking the return value of every call to trace_seq_printf()
> and friends, they can all be called normally, and at the end we can
> return !trace_seq_has_overflowed() instead.
>
> Several functions also return TRACE_TYPE_PARTIAL_LINE when the trace_seq
> overflowed and TRACE_TYPE_HANDLED otherwise. Another helper function
> was created called trace_handle_return() which takes a trace_seq and
> returns these enums. Using this helper function also simplifies the
> code.
>
> This change also makes it possible to remove the return values of
> trace_seq_printf() and friends. They should instead just be
> void functions.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> include/linux/ftrace_event.h | 11 ++
> include/linux/trace_seq.h | 12 ++
> include/trace/ftrace.h | 6 +-
> kernel/trace/trace.c | 69 +++----
> kernel/trace/trace.h | 1 +
> kernel/trace/trace_output.c | 416 +++++++++++++++++--------------------------
> kernel/trace/trace_output.h | 16 +-
> 7 files changed, 231 insertions(+), 300 deletions(-)
[...]
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index cfa91de22e27..163c11b6b8ff 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
[...]
> @@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> struct trace_seq *s = &iter->seq;
> struct trace_seq *p = &iter->tmp_seq;
> struct trace_entry *entry;
> - int ret;
>
> event = container_of(trace_event, struct ftrace_event_call, event);
> entry = iter->ent;
> @@ -204,8 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> }
>
> trace_seq_init(p);
> - ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> - if (!ret)
> + trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> +
> + if (trace_seq_has_overflowed(s))
> return TRACE_TYPE_PARTIAL_LINE;
>
> return 0;
This looks like a bug in the original code. It returns 0 in each case
because TRACE_TYPE_PARTIAL_LINE == 0. I guess that the last three
lines should get replaced by
return trace_handle_return(s);
as it is done in the other functions.
[...]
> @@ -320,14 +302,14 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
> if (file) {
> ret = trace_seq_path(s, &file->f_path);
> if (ret)
I think that we could ignore the return value from trace_seq_path() as
well. The other trace_seq*() writes will be NOP if there is an
overflow.
Or do you have some special plans with trace_seq_path(), please?
> - ret = trace_seq_printf(s, "[+0x%lx]",
> - ip - vmstart);
> + trace_seq_printf(s, "[+0x%lx]",
> + ip - vmstart);
> }
> up_read(&mm->mmap_sem);
> }
> if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
> - ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
> - return ret;
> + trace_seq_printf(s, " <" IP_FMT ">", ip);
> + return !trace_seq_has_overflowed(s);
> }
The wrong return value was there even before. The other problem is
just another optimization. Feel free to solve them later in another
patch(set).
I really like the simplification.
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Best Regards,
Petr
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return()
2014-11-14 11:25 ` Petr Mladek
@ 2014-11-14 11:58 ` Steven Rostedt
2014-11-14 18:21 ` Steven Rostedt
1 sibling, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 11:58 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 12:25:23 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> On Thu 2014-11-13 20:12:46, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > Adding a trace_seq_has_overflowed() which returns true if the trace_seq
> > had too much written into it allows us to simplify the code.
> >
> > Instead of checking the return value of every call to trace_seq_printf()
> > and friends, they can all be called normally, and at the end we can
> > return !trace_seq_has_overflowed() instead.
> >
> > Several functions also return TRACE_TYPE_PARTIAL_LINE when the trace_seq
> > overflowed and TRACE_TYPE_HANDLED otherwise. Another helper function
> > was created called trace_handle_return() which takes a trace_seq and
> > returns these enums. Using this helper function also simplifies the
> > code.
> >
> > This change also makes it possible to remove the return values of
> > trace_seq_printf() and friends. They should instead just be
> > void functions.
> >
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > include/linux/ftrace_event.h | 11 ++
> > include/linux/trace_seq.h | 12 ++
> > include/trace/ftrace.h | 6 +-
> > kernel/trace/trace.c | 69 +++----
> > kernel/trace/trace.h | 1 +
> > kernel/trace/trace_output.c | 416 +++++++++++++++++--------------------------
> > kernel/trace/trace_output.h | 16 +-
> > 7 files changed, 231 insertions(+), 300 deletions(-)
>
> [...]
>
> > diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> > index cfa91de22e27..163c11b6b8ff 100644
> > --- a/kernel/trace/trace_output.c
> > +++ b/kernel/trace/trace_output.c
> [...]
> > @@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> > struct trace_seq *s = &iter->seq;
> > struct trace_seq *p = &iter->tmp_seq;
> > struct trace_entry *entry;
> > - int ret;
> >
> > event = container_of(trace_event, struct ftrace_event_call, event);
> > entry = iter->ent;
> > @@ -204,8 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> > }
> >
> > trace_seq_init(p);
> > - ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> > - if (!ret)
> > + trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> > +
> > + if (trace_seq_has_overflowed(s))
> > return TRACE_TYPE_PARTIAL_LINE;
> >
> > return 0;
>
> This looks like a bug in the original code. It returns 0 in each case
> because TRACE_TYPE_PARTIAL_LINE == 0. I guess that the last three
> lines should get replaced by
>
> return trace_handle_return(s);
>
> as it is done in the other functions.
Yes, I noticed this too. As it was a bug in the original code, I left
it. I do plan on changing it though. Thanks for the reminder.
>
> [...]
>
> > @@ -320,14 +302,14 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
> > if (file) {
> > ret = trace_seq_path(s, &file->f_path);
> > if (ret)
>
> I think that we could ignore the return value from trace_seq_path() as
> well. The other trace_seq*() writes will be NOP if there is an
> overflow.
Yes I know this too, and since trace_seq_path() still has a return
value, I left it.
>
> Or do you have some special plans with trace_seq_path(), please?
I want to understand what the seq_path() code does and why Al Viro said
it requires having a return value. I'm just not touching that code
until I have a full understanding. It's not needed for this patch set.
>
> > - ret = trace_seq_printf(s, "[+0x%lx]",
> > - ip - vmstart);
> > + trace_seq_printf(s, "[+0x%lx]",
> > + ip - vmstart);
> > }
> > up_read(&mm->mmap_sem);
> > }
> > if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
> > - ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
> > - return ret;
> > + trace_seq_printf(s, " <" IP_FMT ">", ip);
> > + return !trace_seq_has_overflowed(s);
> > }
>
> The wrong return value was there even before. The other problem is
> just another optimization. Feel free to solve them later in another
> patch(set).
Do you mean your first comment? If so, yeah, that's why I didn't change
it. But I forgot to write a patch to fix it, so thanks for the reminder.
>
> I really like the simplification.
>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return()
2014-11-14 11:25 ` Petr Mladek
2014-11-14 11:58 ` Steven Rostedt
@ 2014-11-14 18:21 ` Steven Rostedt
1 sibling, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 18:21 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 12:25:23 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> > @@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> > struct trace_seq *s = &iter->seq;
> > struct trace_seq *p = &iter->tmp_seq;
> > struct trace_entry *entry;
> > - int ret;
> >
> > event = container_of(trace_event, struct ftrace_event_call, event);
> > entry = iter->ent;
> > @@ -204,8 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
> > }
> >
> > trace_seq_init(p);
> > - ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> > - if (!ret)
> > + trace_seq_printf(s, "%s: ", ftrace_event_name(event));
> > +
> > + if (trace_seq_has_overflowed(s))
> > return TRACE_TYPE_PARTIAL_LINE;
> >
> > return 0;
>
> This looks like a bug in the original code. It returns 0 in each case
> because TRACE_TYPE_PARTIAL_LINE == 0. I guess that the last three
> lines should get replaced by
>
> return trace_handle_return(s);
>
> as it is done in the other functions.
Here's the fix for this:
-- Steve
>From 5986fa1aee34cbfe2513d7a20d2590fb2a1fc1f2 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Fri, 14 Nov 2014 11:42:06 -0500
Subject: [PATCH] tracing: Fix return value of ftrace_raw_output_prep()
If the trace_seq of ftrace_raw_output_prep() is full this function
returns TRACE_TYPE_PARTIAL_LINE, otherwise it returns zero.
The problem is that TRACE_TYPE_PARTIAL_LINE happens to be zero!
The thing is, the caller of ftrace_raw_output_prep() expects a
success to be zero. Change that to expect it to be
TRACE_TYPE_HANDLED.
Link: http://lkml.kernel.org/r/20141114112522.GA2988@dhcp128.suse.cz
Reminded-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/trace/ftrace.h | 2 +-
kernel/trace/trace_output.c | 5 +----
2 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index f13471b5d27a..139b5067345b 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -277,7 +277,7 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags, \
field = (typeof(field))iter->ent; \
\
ret = ftrace_raw_output_prep(iter, trace_event); \
- if (ret) \
+ if (ret != TRACE_TYPE_HANDLED) \
return ret; \
\
trace_seq_printf(s, print); \
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 163c11b6b8ff..723818bc83b4 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -196,10 +196,7 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
trace_seq_init(p);
trace_seq_printf(s, "%s: ", ftrace_event_name(event));
- if (trace_seq_has_overflowed(s))
- return TRACE_TYPE_PARTIAL_LINE;
-
- return 0;
+ return trace_handle_return(s);
}
EXPORT_SYMBOL(ftrace_raw_output_prep);
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 03/23 v4] blktrace/tracing: Use trace_seq_has_overflowed() helper function
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 01/23 v4] tracing: Fix trace_seq_bitmask() to start at current position Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 02/23 v4] tracing: Add trace_seq_has_overflowed() and trace_handle_return() Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 04/23 v4] ring-buffer: Remove check of trace_seq_{puts,printf}() return values Steven Rostedt
` (19 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek, Jens Axboe
[-- Attachment #1: 0003-blktrace-tracing-Use-trace_seq_has_overflowed-helper.patch --]
[-- Type: text/plain, Size: 10179 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Checking the return code of every trace_seq_printf() operation and having
to return early if it overflowed makes the code messy.
Using the new trace_seq_has_overflowed() and trace_handle_return() functions
allows us to clean up the code.
In the future, trace_seq_printf() and friends will be turning into void
functions and not returning a value. The trace_seq_has_overflowed() is to
be used instead. This cleanup allows that change to take place.
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/blktrace.c | 148 +++++++++++++++++++++---------------------------
1 file changed, 66 insertions(+), 82 deletions(-)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c1bd4ada2a04..11b9cb36092b 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1142,9 +1142,9 @@ static void get_pdu_remap(const struct trace_entry *ent,
r->sector_from = be64_to_cpu(sector_from);
}
-typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
+typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
-static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
+static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
{
char rwbs[RWBS_LEN];
unsigned long long ts = iter->ts;
@@ -1154,33 +1154,33 @@ static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
fill_rwbs(rwbs, t);
- return trace_seq_printf(&iter->seq,
- "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
- MAJOR(t->device), MINOR(t->device), iter->cpu,
- secs, nsec_rem, iter->ent->pid, act, rwbs);
+ trace_seq_printf(&iter->seq,
+ "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), iter->cpu,
+ secs, nsec_rem, iter->ent->pid, act, rwbs);
}
-static int blk_log_action(struct trace_iterator *iter, const char *act)
+static void blk_log_action(struct trace_iterator *iter, const char *act)
{
char rwbs[RWBS_LEN];
const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
fill_rwbs(rwbs, t);
- return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
- MAJOR(t->device), MINOR(t->device), act, rwbs);
+ trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), act, rwbs);
}
-static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
{
const unsigned char *pdu_buf;
int pdu_len;
- int i, end, ret;
+ int i, end;
pdu_buf = pdu_start(ent);
pdu_len = te_blk_io_trace(ent)->pdu_len;
if (!pdu_len)
- return 1;
+ return;
/* find the last zero that needs to be printed */
for (end = pdu_len - 1; end >= 0; end--)
@@ -1188,119 +1188,107 @@ static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
break;
end++;
- if (!trace_seq_putc(s, '('))
- return 0;
+ trace_seq_putc(s, '(');
for (i = 0; i < pdu_len; i++) {
- ret = trace_seq_printf(s, "%s%02x",
- i == 0 ? "" : " ", pdu_buf[i]);
- if (!ret)
- return ret;
+ trace_seq_printf(s, "%s%02x",
+ i == 0 ? "" : " ", pdu_buf[i]);
/*
* stop when the rest is just zeroes and indicate so
* with a ".." appended
*/
- if (i == end && end != pdu_len - 1)
- return trace_seq_puts(s, " ..) ");
+ if (i == end && end != pdu_len - 1) {
+ trace_seq_puts(s, " ..) ");
+ return;
+ }
}
- return trace_seq_puts(s, ") ");
+ trace_seq_puts(s, ") ");
}
-static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
{
char cmd[TASK_COMM_LEN];
trace_find_cmdline(ent->pid, cmd);
if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
- int ret;
-
- ret = trace_seq_printf(s, "%u ", t_bytes(ent));
- if (!ret)
- return 0;
- ret = blk_log_dump_pdu(s, ent);
- if (!ret)
- return 0;
- return trace_seq_printf(s, "[%s]\n", cmd);
+ trace_seq_printf(s, "%u ", t_bytes(ent));
+ blk_log_dump_pdu(s, ent);
+ trace_seq_printf(s, "[%s]\n", cmd);
} else {
if (t_sec(ent))
- return trace_seq_printf(s, "%llu + %u [%s]\n",
+ trace_seq_printf(s, "%llu + %u [%s]\n",
t_sector(ent), t_sec(ent), cmd);
- return trace_seq_printf(s, "[%s]\n", cmd);
+ else
+ trace_seq_printf(s, "[%s]\n", cmd);
}
}
-static int blk_log_with_error(struct trace_seq *s,
+static void blk_log_with_error(struct trace_seq *s,
const struct trace_entry *ent)
{
if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
- int ret;
-
- ret = blk_log_dump_pdu(s, ent);
- if (ret)
- return trace_seq_printf(s, "[%d]\n", t_error(ent));
- return 0;
+ blk_log_dump_pdu(s, ent);
+ trace_seq_printf(s, "[%d]\n", t_error(ent));
} else {
if (t_sec(ent))
- return trace_seq_printf(s, "%llu + %u [%d]\n",
- t_sector(ent),
- t_sec(ent), t_error(ent));
- return trace_seq_printf(s, "%llu [%d]\n",
- t_sector(ent), t_error(ent));
+ trace_seq_printf(s, "%llu + %u [%d]\n",
+ t_sector(ent),
+ t_sec(ent), t_error(ent));
+ else
+ trace_seq_printf(s, "%llu [%d]\n",
+ t_sector(ent), t_error(ent));
}
}
-static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
{
struct blk_io_trace_remap r = { .device_from = 0, };
get_pdu_remap(ent, &r);
- return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
- t_sector(ent), t_sec(ent),
- MAJOR(r.device_from), MINOR(r.device_from),
- (unsigned long long)r.sector_from);
+ trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+ t_sector(ent), t_sec(ent),
+ MAJOR(r.device_from), MINOR(r.device_from),
+ (unsigned long long)r.sector_from);
}
-static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
{
char cmd[TASK_COMM_LEN];
trace_find_cmdline(ent->pid, cmd);
- return trace_seq_printf(s, "[%s]\n", cmd);
+ trace_seq_printf(s, "[%s]\n", cmd);
}
-static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
{
char cmd[TASK_COMM_LEN];
trace_find_cmdline(ent->pid, cmd);
- return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
+ trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
}
-static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
{
char cmd[TASK_COMM_LEN];
trace_find_cmdline(ent->pid, cmd);
- return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
- get_pdu_int(ent), cmd);
+ trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+ get_pdu_int(ent), cmd);
}
-static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
{
- int ret;
const struct blk_io_trace *t = te_blk_io_trace(ent);
- ret = trace_seq_putmem(s, t + 1, t->pdu_len);
- if (ret)
- return trace_seq_putc(s, '\n');
- return ret;
+ trace_seq_putmem(s, t + 1, t->pdu_len);
+ trace_seq_putc(s, '\n');
}
/*
@@ -1339,7 +1327,7 @@ static void blk_tracer_reset(struct trace_array *tr)
static const struct {
const char *act[2];
- int (*print)(struct trace_seq *s, const struct trace_entry *ent);
+ void (*print)(struct trace_seq *s, const struct trace_entry *ent);
} what2act[] = {
[__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
[__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
@@ -1364,7 +1352,6 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
struct trace_seq *s = &iter->seq;
const struct blk_io_trace *t;
u16 what;
- int ret;
bool long_act;
blk_log_action_t *log_action;
@@ -1374,21 +1361,18 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
log_action = classic ? &blk_log_action_classic : &blk_log_action;
if (t->action == BLK_TN_MESSAGE) {
- ret = log_action(iter, long_act ? "message" : "m");
- if (ret)
- ret = blk_log_msg(s, iter->ent);
- goto out;
+ log_action(iter, long_act ? "message" : "m");
+ blk_log_msg(s, iter->ent);
}
if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
- ret = trace_seq_printf(s, "Unknown action %x\n", what);
+ trace_seq_printf(s, "Unknown action %x\n", what);
else {
- ret = log_action(iter, what2act[what].act[long_act]);
- if (ret)
- ret = what2act[what].print(s, iter->ent);
+ log_action(iter, what2act[what].act[long_act]);
+ what2act[what].print(s, iter->ent);
}
-out:
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+
+ return trace_handle_return(s);
}
static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
@@ -1397,7 +1381,7 @@ static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
return print_one_line(iter, false);
}
-static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
+static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
@@ -1407,18 +1391,18 @@ static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
.time = iter->ts,
};
- if (!trace_seq_putmem(s, &old, offset))
- return 0;
- return trace_seq_putmem(s, &t->sector,
- sizeof(old) - offset + t->pdu_len);
+ trace_seq_putmem(s, &old, offset);
+ trace_seq_putmem(s, &t->sector,
+ sizeof(old) - offset + t->pdu_len);
}
static enum print_line_t
blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
struct trace_event *event)
{
- return blk_trace_synthesize_old_trace(iter) ?
- TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+ blk_trace_synthesize_old_trace(iter);
+
+ return trace_handle_return(&iter->seq);
}
static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 04/23 v4] ring-buffer: Remove check of trace_seq_{puts,printf}() return values
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (2 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 03/23 v4] blktrace/tracing: Use trace_seq_has_overflowed() helper function Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 05/23 v4] tracing: Have branch tracer use trace_handle_return() helper function Steven Rostedt
` (18 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0004-ring-buffer-Remove-check-of-trace_seq_-puts-printf-r.patch --]
[-- Type: text/plain, Size: 4025 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Remove checking the return value of all trace_seq_puts(). It was wrong
anyway as only the last return value mattered. But as the trace_seq_puts()
is going to be a void function in the future, we should not be checking
the return value of it anyway.
Just return !trace_seq_has_overflowed() instead.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/ring_buffer.c | 75 ++++++++++++++++++++++------------------------
1 file changed, 36 insertions(+), 39 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2d75c94ae87d..a28bdd17c853 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -34,21 +34,19 @@ static void update_pages_handler(struct work_struct *work);
*/
int ring_buffer_print_entry_header(struct trace_seq *s)
{
- int ret;
-
- ret = trace_seq_puts(s, "# compressed entry header\n");
- ret = trace_seq_puts(s, "\ttype_len : 5 bits\n");
- ret = trace_seq_puts(s, "\ttime_delta : 27 bits\n");
- ret = trace_seq_puts(s, "\tarray : 32 bits\n");
- ret = trace_seq_putc(s, '\n');
- ret = trace_seq_printf(s, "\tpadding : type == %d\n",
- RINGBUF_TYPE_PADDING);
- ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
- RINGBUF_TYPE_TIME_EXTEND);
- ret = trace_seq_printf(s, "\tdata max type_len == %d\n",
- RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+ trace_seq_puts(s, "# compressed entry header\n");
+ trace_seq_puts(s, "\ttype_len : 5 bits\n");
+ trace_seq_puts(s, "\ttime_delta : 27 bits\n");
+ trace_seq_puts(s, "\tarray : 32 bits\n");
+ trace_seq_putc(s, '\n');
+ trace_seq_printf(s, "\tpadding : type == %d\n",
+ RINGBUF_TYPE_PADDING);
+ trace_seq_printf(s, "\ttime_extend : type == %d\n",
+ RINGBUF_TYPE_TIME_EXTEND);
+ trace_seq_printf(s, "\tdata max type_len == %d\n",
+ RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
- return ret;
+ return !trace_seq_has_overflowed(s);
}
/*
@@ -419,32 +417,31 @@ static inline int test_time_stamp(u64 delta)
int ring_buffer_print_page_header(struct trace_seq *s)
{
struct buffer_data_page field;
- int ret;
-
- ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
- "offset:0;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)sizeof(field.time_stamp),
- (unsigned int)is_signed_type(u64));
-
- ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- (unsigned int)sizeof(field.commit),
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- 1,
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: char data;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), data),
- (unsigned int)BUF_PAGE_SIZE,
- (unsigned int)is_signed_type(char));
- return ret;
+ trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+ "offset:0;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)sizeof(field.time_stamp),
+ (unsigned int)is_signed_type(u64));
+
+ trace_seq_printf(s, "\tfield: local_t commit;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ (unsigned int)sizeof(field.commit),
+ (unsigned int)is_signed_type(long));
+
+ trace_seq_printf(s, "\tfield: int overwrite;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ 1,
+ (unsigned int)is_signed_type(long));
+
+ trace_seq_printf(s, "\tfield: char data;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), data),
+ (unsigned int)BUF_PAGE_SIZE,
+ (unsigned int)is_signed_type(char));
+
+ return !trace_seq_has_overflowed(s);
}
struct rb_irq_work {
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 05/23 v4] tracing: Have branch tracer use trace_handle_return() helper function
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (3 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 04/23 v4] ring-buffer: Remove check of trace_seq_{puts,printf}() return values Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed() Steven Rostedt
` (17 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0005-tracing-Have-branch-tracer-use-trace_handle_return-h.patch --]
[-- Type: text/plain, Size: 1285 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The branch tracer should not be checking the trace_seq_printf() return value
as that will soon be void. There's a new trace_handle_return() helper function
that will return TRACE_TYPE_PARTIAL_LINE if the trace_seq overflowed
and TRACE_TYPE_HANDLED otherwise.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_branch.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 697fb9bac8f0..42c85036fc3f 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -151,14 +151,13 @@ static enum print_line_t trace_branch_print(struct trace_iterator *iter,
trace_assign_type(field, iter->ent);
- if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
- field->correct ? " ok " : " MISS ",
- field->func,
- field->file,
- field->line))
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
+ field->correct ? " ok " : " MISS ",
+ field->func,
+ field->file,
+ field->line);
+
+ return trace_handle_return(&iter->seq);
}
static void branch_print_header(struct seq_file *s)
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed()
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (4 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 05/23 v4] tracing: Have branch tracer use trace_handle_return() helper function Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 12:41 ` Petr Mladek
2014-11-14 1:12 ` [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks Steven Rostedt
` (16 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0006-tracing-Have-function_graph-use-trace_seq_has_overfl.patch --]
[-- Type: text/plain, Size: 19239 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Instead of doing individual checks all over the place that makes the code
very messy. Just check trace_seq_has_overflowed() at the end or in
strategic places.
This makes the code much cleaner and also helps with getting closer
to removing the return values of trace_seq_printf() and friends.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.h | 2 +-
kernel/trace/trace_functions_graph.c | 374 +++++++++++------------------------
2 files changed, 116 insertions(+), 260 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 19418221b302..c3a37e55ec8b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -726,7 +726,7 @@ extern unsigned long trace_flags;
extern enum print_line_t
print_graph_function_flags(struct trace_iterator *iter, u32 flags);
extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
-extern enum print_line_t
+extern void
trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
extern void graph_trace_open(struct trace_iterator *iter);
extern void graph_trace_close(struct trace_iterator *iter);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index f0a0c982cde3..477a7c65cf08 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -107,7 +107,7 @@ enum {
FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
};
-static enum print_line_t
+static void
print_graph_duration(unsigned long long duration, struct trace_seq *s,
u32 flags);
@@ -483,33 +483,24 @@ static int graph_trace_update_thresh(struct trace_array *tr)
static int max_bytes_for_cpu;
-static enum print_line_t
-print_graph_cpu(struct trace_seq *s, int cpu)
+static void print_graph_cpu(struct trace_seq *s, int cpu)
{
- int ret;
-
/*
* Start with a space character - to make it stand out
* to the right a bit when trace output is pasted into
* email:
*/
- ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
}
#define TRACE_GRAPH_PROCINFO_LENGTH 14
-static enum print_line_t
-print_graph_proc(struct trace_seq *s, pid_t pid)
+static void print_graph_proc(struct trace_seq *s, pid_t pid)
{
char comm[TASK_COMM_LEN];
/* sign + log10(MAX_INT) + '\0' */
char pid_str[11];
int spaces = 0;
- int ret;
int len;
int i;
@@ -524,56 +515,43 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
/* First spaces to align center */
- for (i = 0; i < spaces / 2; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ for (i = 0; i < spaces / 2; i++)
+ trace_seq_putc(s, ' ');
- ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s-%s", comm, pid_str);
/* Last spaces to align center */
- for (i = 0; i < spaces - (spaces / 2); i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
- return TRACE_TYPE_HANDLED;
+ for (i = 0; i < spaces - (spaces / 2); i++)
+ trace_seq_putc(s, ' ');
}
-static enum print_line_t
-print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
{
- if (!trace_seq_putc(s, ' '))
- return 0;
-
- return trace_print_lat_fmt(s, entry);
+ trace_seq_putc(s, ' ');
+ trace_print_lat_fmt(s, entry);
}
/* If the pid changed since the last trace, output this event */
-static enum print_line_t
+static void
verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
{
pid_t prev_pid;
pid_t *last_pid;
- int ret;
if (!data)
- return TRACE_TYPE_HANDLED;
+ return;
last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
if (*last_pid == pid)
- return TRACE_TYPE_HANDLED;
+ return;
prev_pid = *last_pid;
*last_pid = pid;
if (prev_pid == -1)
- return TRACE_TYPE_HANDLED;
+ return;
/*
* Context-switch trace line:
@@ -582,33 +560,12 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
------------------------------------------
*/
- ret = trace_seq_puts(s,
- " ------------------------------------------\n");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = print_graph_cpu(s, cpu);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = print_graph_proc(s, prev_pid);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = trace_seq_puts(s, " => ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = print_graph_proc(s, pid);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = trace_seq_puts(s,
- "\n ------------------------------------------\n\n");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- return TRACE_TYPE_HANDLED;
+ trace_seq_puts(s, " ------------------------------------------\n");
+ print_graph_cpu(s, cpu);
+ print_graph_proc(s, prev_pid);
+ trace_seq_puts(s, " => ");
+ print_graph_proc(s, pid);
+ trace_seq_puts(s, "\n ------------------------------------------\n\n");
}
static struct ftrace_graph_ret_entry *
@@ -682,94 +639,69 @@ get_return_for_leaf(struct trace_iterator *iter,
return next;
}
-static int print_graph_abs_time(u64 t, struct trace_seq *s)
+static void print_graph_abs_time(u64 t, struct trace_seq *s)
{
unsigned long usecs_rem;
usecs_rem = do_div(t, NSEC_PER_SEC);
usecs_rem /= 1000;
- return trace_seq_printf(s, "%5lu.%06lu | ",
- (unsigned long)t, usecs_rem);
+ trace_seq_printf(s, "%5lu.%06lu | ",
+ (unsigned long)t, usecs_rem);
}
-static enum print_line_t
+static void
print_graph_irq(struct trace_iterator *iter, unsigned long addr,
enum trace_type type, int cpu, pid_t pid, u32 flags)
{
- int ret;
struct trace_seq *s = &iter->seq;
if (addr < (unsigned long)__irqentry_text_start ||
addr >= (unsigned long)__irqentry_text_end)
- return TRACE_TYPE_UNHANDLED;
+ return;
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
/* Absolute time */
- if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
- ret = print_graph_abs_time(iter->ts, s);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+ print_graph_abs_time(iter->ts, s);
/* Cpu */
- if (flags & TRACE_GRAPH_PRINT_CPU) {
- ret = print_graph_cpu(s, cpu);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (flags & TRACE_GRAPH_PRINT_CPU)
+ print_graph_cpu(s, cpu);
/* Proc */
if (flags & TRACE_GRAPH_PRINT_PROC) {
- ret = print_graph_proc(s, pid);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_puts(s, " | ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_proc(s, pid);
+ trace_seq_puts(s, " | ");
}
}
/* No overhead */
- ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
- if (ret != TRACE_TYPE_HANDLED)
- return ret;
+ print_graph_duration(0, s, flags | FLAGS_FILL_START);
if (type == TRACE_GRAPH_ENT)
- ret = trace_seq_puts(s, "==========>");
+ trace_seq_puts(s, "==========>");
else
- ret = trace_seq_puts(s, "<==========");
-
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
- if (ret != TRACE_TYPE_HANDLED)
- return ret;
-
- ret = trace_seq_putc(s, '\n');
+ trace_seq_puts(s, "<==========");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- return TRACE_TYPE_HANDLED;
+ print_graph_duration(0, s, flags | FLAGS_FILL_END);
+ trace_seq_putc(s, '\n');
}
-enum print_line_t
+void
trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
{
unsigned long nsecs_rem = do_div(duration, 1000);
/* log10(ULONG_MAX) + '\0' */
char msecs_str[21];
char nsecs_str[5];
- int ret, len;
+ int len;
int i;
sprintf(msecs_str, "%lu", (unsigned long) duration);
/* Print msecs */
- ret = trace_seq_printf(s, "%s", msecs_str);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s", msecs_str);
len = strlen(msecs_str);
@@ -778,79 +710,63 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
- ret = trace_seq_printf(s, ".%s", nsecs_str);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, ".%s", nsecs_str);
len += strlen(nsecs_str);
}
- ret = trace_seq_puts(s, " us ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, " us ");
/* Print remaining spaces to fit the row's width */
- for (i = len; i < 7; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
- return TRACE_TYPE_HANDLED;
+ for (i = len; i < 7; i++)
+ trace_seq_putc(s, ' ');
}
-static enum print_line_t
+static void
print_graph_duration(unsigned long long duration, struct trace_seq *s,
u32 flags)
{
- int ret = -1;
+ bool duration_printed = false;
if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
!(trace_flags & TRACE_ITER_CONTEXT_INFO))
- return TRACE_TYPE_HANDLED;
+ return;
/* No real adata, just filling the column with spaces */
switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
case FLAGS_FILL_FULL:
- ret = trace_seq_puts(s, " | ");
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, " | ");
+ return;
case FLAGS_FILL_START:
- ret = trace_seq_puts(s, " ");
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, " ");
+ return;
case FLAGS_FILL_END:
- ret = trace_seq_puts(s, " |");
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, " |");
+ return;
}
/* Signal a overhead of time execution to the output */
if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
/* Duration exceeded 100 msecs */
- if (duration > 100000ULL)
- ret = trace_seq_puts(s, "! ");
+ if (duration > 100000ULL) {
+ trace_seq_puts(s, "! ");
+ duration_printed = true;
+
/* Duration exceeded 10 msecs */
- else if (duration > 10000ULL)
- ret = trace_seq_puts(s, "+ ");
+ } else if (duration > 10000ULL) {
+ trace_seq_puts(s, "+ ");
+ duration_printed = true;
+ }
}
/*
- * The -1 means we either did not exceed the duration tresholds
- * or we dont want to print out the overhead. Either way we need
- * to fill out the space.
+ * If we did not exceed the duration tresholds or we dont want
+ * to print out the overhead. Either way we need to fill out the space.
*/
- if (ret == -1)
- ret = trace_seq_puts(s, " ");
-
- /* Catching here any failure happenned above */
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = trace_print_graph_duration(duration, s);
- if (ret != TRACE_TYPE_HANDLED)
- return ret;
-
- ret = trace_seq_puts(s, "| ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (!duration_printed)
+ trace_seq_puts(s, " ");
- return TRACE_TYPE_HANDLED;
+ trace_print_graph_duration(duration, s);
+ trace_seq_puts(s, "| ");
}
/* Case of a leaf function on its call entry */
@@ -864,7 +780,6 @@ print_graph_entry_leaf(struct trace_iterator *iter,
struct ftrace_graph_ret *graph_ret;
struct ftrace_graph_ent *call;
unsigned long long duration;
- int ret;
int i;
graph_ret = &ret_entry->ret;
@@ -890,22 +805,15 @@ print_graph_entry_leaf(struct trace_iterator *iter,
}
/* Overhead and duration */
- ret = print_graph_duration(duration, s, flags);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_duration(duration, s, flags);
/* Function */
- for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+ trace_seq_putc(s, ' ');
- ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%ps();\n", (void *)call->func);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t
@@ -915,7 +823,6 @@ print_graph_entry_nested(struct trace_iterator *iter,
{
struct ftrace_graph_ent *call = &entry->graph_ent;
struct fgraph_data *data = iter->private;
- int ret;
int i;
if (data) {
@@ -931,19 +838,15 @@ print_graph_entry_nested(struct trace_iterator *iter,
}
/* No time */
- ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
- if (ret != TRACE_TYPE_HANDLED)
- return ret;
+ print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
/* Function */
- for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+ trace_seq_putc(s, ' ');
- ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
- if (!ret)
+ trace_seq_printf(s, "%ps() {\n", (void *)call->func);
+
+ if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
/*
@@ -953,62 +856,43 @@ print_graph_entry_nested(struct trace_iterator *iter,
return TRACE_TYPE_NO_CONSUME;
}
-static enum print_line_t
+static void
print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
int type, unsigned long addr, u32 flags)
{
struct fgraph_data *data = iter->private;
struct trace_entry *ent = iter->ent;
int cpu = iter->cpu;
- int ret;
/* Pid */
- if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
+ verif_pid(s, ent->pid, cpu, data);
- if (type) {
+ if (type)
/* Interrupt */
- ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
- return 0;
+ return;
/* Absolute time */
- if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
- ret = print_graph_abs_time(iter->ts, s);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+ print_graph_abs_time(iter->ts, s);
/* Cpu */
- if (flags & TRACE_GRAPH_PRINT_CPU) {
- ret = print_graph_cpu(s, cpu);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (flags & TRACE_GRAPH_PRINT_CPU)
+ print_graph_cpu(s, cpu);
/* Proc */
if (flags & TRACE_GRAPH_PRINT_PROC) {
- ret = print_graph_proc(s, ent->pid);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
-
- ret = trace_seq_puts(s, " | ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_proc(s, ent->pid);
+ trace_seq_puts(s, " | ");
}
/* Latency format */
- if (trace_flags & TRACE_ITER_LATENCY_FMT) {
- ret = print_graph_lat_fmt(s, ent);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (trace_flags & TRACE_ITER_LATENCY_FMT)
+ print_graph_lat_fmt(s, ent);
- return 0;
+ return;
}
/*
@@ -1126,8 +1010,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
if (check_irq_entry(iter, flags, call->func, call->depth))
return TRACE_TYPE_HANDLED;
- if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
leaf_ret = get_return_for_leaf(iter, field);
if (leaf_ret)
@@ -1160,7 +1043,6 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
pid_t pid = ent->pid;
int cpu = iter->cpu;
int func_match = 1;
- int ret;
int i;
if (check_irq_return(iter, flags, trace->depth))
@@ -1186,20 +1068,14 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
}
}
- if (print_graph_prologue(iter, s, 0, 0, flags))
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_prologue(iter, s, 0, 0, flags);
/* Overhead and duration */
- ret = print_graph_duration(duration, s, flags);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_duration(duration, s, flags);
/* Closing brace */
- for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
+ trace_seq_putc(s, ' ');
/*
* If the return function does not have a matching entry,
@@ -1208,30 +1084,20 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
* belongs to, write out the function name. Always do
* that if the funcgraph-tail option is enabled.
*/
- if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) {
- ret = trace_seq_puts(s, "}\n");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- } else {
- ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
+ trace_seq_puts(s, "}\n");
+ else
+ trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
/* Overrun */
- if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
- ret = trace_seq_printf(s, " (Overruns: %lu)\n",
- trace->overrun);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (flags & TRACE_GRAPH_PRINT_OVERRUN)
+ trace_seq_printf(s, " (Overruns: %lu)\n",
+ trace->overrun);
- ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
- cpu, pid, flags);
- if (ret == TRACE_TYPE_PARTIAL_LINE)
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
+ cpu, pid, flags);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t
@@ -1248,26 +1114,18 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
if (data)
depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
- if (print_graph_prologue(iter, s, 0, 0, flags))
- return TRACE_TYPE_PARTIAL_LINE;
+ print_graph_prologue(iter, s, 0, 0, flags);
/* No time */
- ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
- if (ret != TRACE_TYPE_HANDLED)
- return ret;
+ print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
/* Indentation */
if (depth > 0)
- for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
- ret = trace_seq_putc(s, ' ');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
+ trace_seq_putc(s, ' ');
/* The comment */
- ret = trace_seq_puts(s, "/* ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, "/* ");
switch (iter->ent->type) {
case TRACE_BPRINT:
@@ -1296,11 +1154,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
s->len--;
}
- ret = trace_seq_puts(s, " */\n");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, " */\n");
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed()
2014-11-14 1:12 ` [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed() Steven Rostedt
@ 2014-11-14 12:41 ` Petr Mladek
2014-11-14 12:52 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 12:41 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:12:50, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Instead of doing individual checks all over the place that makes the code
> very messy. Just check trace_seq_has_overflowed() at the end or in
> strategic places.
>
> This makes the code much cleaner and also helps with getting closer
> to removing the return values of trace_seq_printf() and friends.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace.h | 2 +-
> kernel/trace/trace_functions_graph.c | 374 +++++++++++------------------------
> 2 files changed, 116 insertions(+), 260 deletions(-)
>
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 19418221b302..c3a37e55ec8b 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -726,7 +726,7 @@ extern unsigned long trace_flags;
> extern enum print_line_t
> print_graph_function_flags(struct trace_iterator *iter, u32 flags);
> extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
> -extern enum print_line_t
> +extern void
> trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
> extern void graph_trace_open(struct trace_iterator *iter);
> extern void graph_trace_close(struct trace_iterator *iter);
> diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
> index f0a0c982cde3..477a7c65cf08 100644
> --- a/kernel/trace/trace_functions_graph.c
> +++ b/kernel/trace/trace_functions_graph.c
[...]
> @@ -682,94 +639,69 @@ get_return_for_leaf(struct trace_iterator *iter,
> return next;
> }
>
> -static int print_graph_abs_time(u64 t, struct trace_seq *s)
> +static void print_graph_abs_time(u64 t, struct trace_seq *s)
> {
> unsigned long usecs_rem;
>
> usecs_rem = do_div(t, NSEC_PER_SEC);
> usecs_rem /= 1000;
>
> - return trace_seq_printf(s, "%5lu.%06lu | ",
> - (unsigned long)t, usecs_rem);
> + trace_seq_printf(s, "%5lu.%06lu | ",
> + (unsigned long)t, usecs_rem);
> }
>
> -static enum print_line_t
> +static void
> print_graph_irq(struct trace_iterator *iter, unsigned long addr,
> enum trace_type type, int cpu, pid_t pid, u32 flags)
> {
> - int ret;
> struct trace_seq *s = &iter->seq;
>
> if (addr < (unsigned long)__irqentry_text_start ||
> addr >= (unsigned long)__irqentry_text_end)
> - return TRACE_TYPE_UNHANDLED;
> + return;
I was curious if the TRACE_TYPE_UNHANDLED return value has any special
effect. But it seems to be ignored. There are only two callers and
they take care only of the PARTIAL_LINE return value.
[...]
> @@ -953,62 +856,43 @@ print_graph_entry_nested(struct trace_iterator *iter,
> return TRACE_TYPE_NO_CONSUME;
> }
>
> -static enum print_line_t
> +static void
> print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
> int type, unsigned long addr, u32 flags)
> {
> struct fgraph_data *data = iter->private;
> struct trace_entry *ent = iter->ent;
> int cpu = iter->cpu;
> - int ret;
>
> /* Pid */
> - if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
> - return TRACE_TYPE_PARTIAL_LINE;
> + verif_pid(s, ent->pid, cpu, data);
>
> - if (type) {
> + if (type)
> /* Interrupt */
> - ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
> - if (ret == TRACE_TYPE_PARTIAL_LINE)
> - return TRACE_TYPE_PARTIAL_LINE;
> - }
> + print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
>
> if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
> - return 0;
> + return;
>
> /* Absolute time */
> - if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
> - ret = print_graph_abs_time(iter->ts, s);
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> - }
> + if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
> + print_graph_abs_time(iter->ts, s);
>
> /* Cpu */
> - if (flags & TRACE_GRAPH_PRINT_CPU) {
> - ret = print_graph_cpu(s, cpu);
> - if (ret == TRACE_TYPE_PARTIAL_LINE)
> - return TRACE_TYPE_PARTIAL_LINE;
> - }
> + if (flags & TRACE_GRAPH_PRINT_CPU)
> + print_graph_cpu(s, cpu);
>
> /* Proc */
> if (flags & TRACE_GRAPH_PRINT_PROC) {
> - ret = print_graph_proc(s, ent->pid);
> - if (ret == TRACE_TYPE_PARTIAL_LINE)
> - return TRACE_TYPE_PARTIAL_LINE;
> -
> - ret = trace_seq_puts(s, " | ");
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> + print_graph_proc(s, ent->pid);
> + trace_seq_puts(s, " | ");
> }
>
> /* Latency format */
> - if (trace_flags & TRACE_ITER_LATENCY_FMT) {
> - ret = print_graph_lat_fmt(s, ent);
> - if (ret == TRACE_TYPE_PARTIAL_LINE)
> - return TRACE_TYPE_PARTIAL_LINE;
> - }
> + if (trace_flags & TRACE_ITER_LATENCY_FMT)
> + print_graph_lat_fmt(s, ent);
>
> - return 0;
> + return;
This probably even fixed a bug. The function returned
TRACE_TYPE_PARTIAL_LINE (0) even when it did not print anything.
The simplification is really cool.
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Best Regards,
Petr Mladek
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed()
2014-11-14 12:41 ` Petr Mladek
@ 2014-11-14 12:52 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 12:52 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 13:41:26 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> > -static enum print_line_t
> > +static void
> > print_graph_irq(struct trace_iterator *iter, unsigned long addr,
> > enum trace_type type, int cpu, pid_t pid, u32 flags)
> > {
> > - int ret;
> > struct trace_seq *s = &iter->seq;
> >
> > if (addr < (unsigned long)__irqentry_text_start ||
> > addr >= (unsigned long)__irqentry_text_end)
> > - return TRACE_TYPE_UNHANDLED;
> > + return;
>
> I was curious if the TRACE_TYPE_UNHANDLED return value has any special
> effect. But it seems to be ignored. There are only two callers and
> they take care only of the PARTIAL_LINE return value.
Yep, I noticed that too, and did the same check before I made the
change. IIRC, that UNHANDLED was written in case anyone did care.
>
> [...]
>
> > @@ -953,62 +856,43 @@ print_graph_entry_nested(struct trace_iterator *iter,
> > return TRACE_TYPE_NO_CONSUME;
> > }
> >
> > -static enum print_line_t
> > +static void
> > print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
> > int type, unsigned long addr, u32 flags)
> > {
> > struct fgraph_data *data = iter->private;
> > struct trace_entry *ent = iter->ent;
> > int cpu = iter->cpu;
> > - int ret;
> >
> > /* Pid */
> > - if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > + verif_pid(s, ent->pid, cpu, data);
> >
> > - if (type) {
> > + if (type)
> > /* Interrupt */
> > - ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
> > - if (ret == TRACE_TYPE_PARTIAL_LINE)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > - }
> > + print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
> >
> > if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
> > - return 0;
> > + return;
> >
> > /* Absolute time */
> > - if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
> > - ret = print_graph_abs_time(iter->ts, s);
> > - if (!ret)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > - }
> > + if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
> > + print_graph_abs_time(iter->ts, s);
> >
> > /* Cpu */
> > - if (flags & TRACE_GRAPH_PRINT_CPU) {
> > - ret = print_graph_cpu(s, cpu);
> > - if (ret == TRACE_TYPE_PARTIAL_LINE)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > - }
> > + if (flags & TRACE_GRAPH_PRINT_CPU)
> > + print_graph_cpu(s, cpu);
> >
> > /* Proc */
> > if (flags & TRACE_GRAPH_PRINT_PROC) {
> > - ret = print_graph_proc(s, ent->pid);
> > - if (ret == TRACE_TYPE_PARTIAL_LINE)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > -
> > - ret = trace_seq_puts(s, " | ");
> > - if (!ret)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > + print_graph_proc(s, ent->pid);
> > + trace_seq_puts(s, " | ");
> > }
> >
> > /* Latency format */
> > - if (trace_flags & TRACE_ITER_LATENCY_FMT) {
> > - ret = print_graph_lat_fmt(s, ent);
> > - if (ret == TRACE_TYPE_PARTIAL_LINE)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > - }
> > + if (trace_flags & TRACE_ITER_LATENCY_FMT)
> > + print_graph_lat_fmt(s, ent);
> >
> > - return 0;
> > + return;
>
> This probably even fixed a bug. The function returned
> TRACE_TYPE_PARTIAL_LINE (0) even when it did not print anything.
>
> The simplification is really cool.
Thanks,
-- Steve
>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
>
> Best Regards,
> Petr Mladek
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (5 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 06/23 v4] tracing: Have function_graph use trace_seq_has_overflowed() Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 5:24 ` Srikar Dronamraju
2014-11-14 14:51 ` Masami Hiramatsu
2014-11-14 1:12 ` [RFC][PATCH 08/23 v4] tracing: Do not check return values of trace_seq_p*() for mmio tracer Steven Rostedt
` (15 subsequent siblings)
22 siblings, 2 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek,
Masami Hiramatsu
[-- Attachment #1: 0007-kprobes-tracing-Use-trace_seq_has_overflowed-for-ove.patch --]
[-- Type: text/plain, Size: 2843 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Instead of checking the return value of trace_seq_printf() and friends
for overflowing of the buffer, use the trace_seq_has_overflowed() helper
function.
This cleans up the code quite a bit and also takes us a step closer to
changing the return values of trace_seq_printf() and friends to void.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_kprobe.c | 42 ++++++++++++++++--------------------------
1 file changed, 16 insertions(+), 26 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 282f6e4e5539..be14b2f091c8 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1024,27 +1024,22 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
field = (struct kprobe_trace_entry_head *)iter->ent;
tp = container_of(event, struct trace_probe, call.event);
- if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
- goto partial;
+ trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
- goto partial;
+ goto out;
- if (!trace_seq_puts(s, ")"))
- goto partial;
+ trace_seq_puts(s, ")");
data = (u8 *)&field[1];
for (i = 0; i < tp->nr_args; i++)
if (!tp->args[i].type->print(s, tp->args[i].name,
data + tp->args[i].offset, field))
- goto partial;
-
- if (!trace_seq_puts(s, "\n"))
- goto partial;
+ goto out;
- return TRACE_TYPE_HANDLED;
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_puts(s, "\n");
+ out:
+ return trace_handle_return(s);
}
static enum print_line_t
@@ -1060,33 +1055,28 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
field = (struct kretprobe_trace_entry_head *)iter->ent;
tp = container_of(event, struct trace_probe, call.event);
- if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
- goto partial;
+ trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
- goto partial;
+ goto out;
- if (!trace_seq_puts(s, " <- "))
- goto partial;
+ trace_seq_puts(s, " <- ");
if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
- goto partial;
+ goto out;
- if (!trace_seq_puts(s, ")"))
- goto partial;
+ trace_seq_puts(s, ")");
data = (u8 *)&field[1];
for (i = 0; i < tp->nr_args; i++)
if (!tp->args[i].type->print(s, tp->args[i].name,
data + tp->args[i].offset, field))
- goto partial;
+ goto out;
- if (!trace_seq_puts(s, "\n"))
- goto partial;
+ trace_seq_puts(s, "\n");
- return TRACE_TYPE_HANDLED;
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ out:
+ return trace_handle_return(s);
}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks
2014-11-14 1:12 ` [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks Steven Rostedt
@ 2014-11-14 5:24 ` Srikar Dronamraju
2014-11-14 14:51 ` Masami Hiramatsu
1 sibling, 0 replies; 58+ messages in thread
From: Srikar Dronamraju @ 2014-11-14 5:24 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Masami Hiramatsu
* Steven Rostedt <rostedt@goodmis.org> [2014-11-13 20:12:51]:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Instead of checking the return value of trace_seq_printf() and friends
> for overflowing of the buffer, use the trace_seq_has_overflowed() helper
> function.
>
> This cleans up the code quite a bit and also takes us a step closer to
> changing the return values of trace_seq_printf() and friends to void.
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Looks good me to me.
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
--
Thanks and Regards
Srikar Dronamraju
^ permalink raw reply [flat|nested] 58+ messages in thread
* Re: [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks
2014-11-14 1:12 ` [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks Steven Rostedt
2014-11-14 5:24 ` Srikar Dronamraju
@ 2014-11-14 14:51 ` Masami Hiramatsu
1 sibling, 0 replies; 58+ messages in thread
From: Masami Hiramatsu @ 2014-11-14 14:51 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek
(2014/11/14 10:12), Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Instead of checking the return value of trace_seq_printf() and friends
> for overflowing of the buffer, use the trace_seq_has_overflowed() helper
> function.
>
> This cleans up the code quite a bit and also takes us a step closer to
> changing the return values of trace_seq_printf() and friends to void.
Looks good to me :)
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Thank you,
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace_kprobe.c | 42 ++++++++++++++++--------------------------
> 1 file changed, 16 insertions(+), 26 deletions(-)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 282f6e4e5539..be14b2f091c8 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1024,27 +1024,22 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
> field = (struct kprobe_trace_entry_head *)iter->ent;
> tp = container_of(event, struct trace_probe, call.event);
>
> - if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
> - goto partial;
> + trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
>
> if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
> - goto partial;
> + goto out;
>
> - if (!trace_seq_puts(s, ")"))
> - goto partial;
> + trace_seq_puts(s, ")");
>
> data = (u8 *)&field[1];
> for (i = 0; i < tp->nr_args; i++)
> if (!tp->args[i].type->print(s, tp->args[i].name,
> data + tp->args[i].offset, field))
> - goto partial;
> -
> - if (!trace_seq_puts(s, "\n"))
> - goto partial;
> + goto out;
>
> - return TRACE_TYPE_HANDLED;
> -partial:
> - return TRACE_TYPE_PARTIAL_LINE;
> + trace_seq_puts(s, "\n");
> + out:
> + return trace_handle_return(s);
> }
>
> static enum print_line_t
> @@ -1060,33 +1055,28 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
> field = (struct kretprobe_trace_entry_head *)iter->ent;
> tp = container_of(event, struct trace_probe, call.event);
>
> - if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
> - goto partial;
> + trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
>
> if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
> - goto partial;
> + goto out;
>
> - if (!trace_seq_puts(s, " <- "))
> - goto partial;
> + trace_seq_puts(s, " <- ");
>
> if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
> - goto partial;
> + goto out;
>
> - if (!trace_seq_puts(s, ")"))
> - goto partial;
> + trace_seq_puts(s, ")");
>
> data = (u8 *)&field[1];
> for (i = 0; i < tp->nr_args; i++)
> if (!tp->args[i].type->print(s, tp->args[i].name,
> data + tp->args[i].offset, field))
> - goto partial;
> + goto out;
>
> - if (!trace_seq_puts(s, "\n"))
> - goto partial;
> + trace_seq_puts(s, "\n");
>
> - return TRACE_TYPE_HANDLED;
> -partial:
> - return TRACE_TYPE_PARTIAL_LINE;
> + out:
> + return trace_handle_return(s);
> }
>
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 08/23 v4] tracing: Do not check return values of trace_seq_p*() for mmio tracer
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (6 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 07/23 v4] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:12 ` [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf() Steven Rostedt
` (14 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0008-tracing-Do-not-check-return-values-of-trace_seq_p-fo.patch --]
[-- Type: text/plain, Size: 5565 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The return values for trace_seq_printf() and friends are going to be
removed and they will become void functions. The mmio tracer checked
their return and even did so incorrectly.
Some of the funtions which returned the values were never checked
themselves. Removing all the checks simplifies the code.
Use trace_seq_has_overflowed() and trace_handle_return() where
necessary instead.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_mmiotrace.c | 52 +++++++++++++++++-------------------------
1 file changed, 21 insertions(+), 31 deletions(-)
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 0abd9b863474..7a9ba62e9fef 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -59,17 +59,15 @@ static void mmio_trace_start(struct trace_array *tr)
mmio_reset_data(tr);
}
-static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
+static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
{
- int ret = 0;
int i;
resource_size_t start, end;
const struct pci_driver *drv = pci_dev_driver(dev);
- /* XXX: incomplete checks for trace_seq_printf() return value */
- ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
- dev->bus->number, dev->devfn,
- dev->vendor, dev->device, dev->irq);
+ trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
+ dev->bus->number, dev->devfn,
+ dev->vendor, dev->device, dev->irq);
/*
* XXX: is pci_resource_to_user() appropriate, since we are
* supposed to interpret the __ioremap() phys_addr argument based on
@@ -77,21 +75,20 @@ static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
*/
for (i = 0; i < 7; i++) {
pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
- ret += trace_seq_printf(s, " %llx",
+ trace_seq_printf(s, " %llx",
(unsigned long long)(start |
(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
}
for (i = 0; i < 7; i++) {
pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
- ret += trace_seq_printf(s, " %llx",
+ trace_seq_printf(s, " %llx",
dev->resource[i].start < dev->resource[i].end ?
(unsigned long long)(end - start) + 1 : 0);
}
if (drv)
- ret += trace_seq_printf(s, " %s\n", drv->name);
+ trace_seq_printf(s, " %s\n", drv->name);
else
- ret += trace_seq_puts(s, " \n");
- return ret;
+ trace_seq_puts(s, " \n");
}
static void destroy_header_iter(struct header_iter *hiter)
@@ -179,28 +176,27 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
unsigned long long t = ns2usecs(iter->ts);
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned secs = (unsigned long)t;
- int ret = 1;
trace_assign_type(field, entry);
rw = &field->rw;
switch (rw->opcode) {
case MMIO_READ:
- ret = trace_seq_printf(s,
+ trace_seq_printf(s,
"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
rw->width, secs, usec_rem, rw->map_id,
(unsigned long long)rw->phys,
rw->value, rw->pc, 0);
break;
case MMIO_WRITE:
- ret = trace_seq_printf(s,
+ trace_seq_printf(s,
"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
rw->width, secs, usec_rem, rw->map_id,
(unsigned long long)rw->phys,
rw->value, rw->pc, 0);
break;
case MMIO_UNKNOWN_OP:
- ret = trace_seq_printf(s,
+ trace_seq_printf(s,
"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
"%02lx 0x%lx %d\n",
secs, usec_rem, rw->map_id,
@@ -209,12 +205,11 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
(rw->value >> 0) & 0xff, rw->pc, 0);
break;
default:
- ret = trace_seq_puts(s, "rw what?\n");
+ trace_seq_puts(s, "rw what?\n");
break;
}
- if (ret)
- return TRACE_TYPE_HANDLED;
- return TRACE_TYPE_PARTIAL_LINE;
+
+ return trace_handle_return(s);
}
static enum print_line_t mmio_print_map(struct trace_iterator *iter)
@@ -226,31 +221,29 @@ static enum print_line_t mmio_print_map(struct trace_iterator *iter)
unsigned long long t = ns2usecs(iter->ts);
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned secs = (unsigned long)t;
- int ret;
trace_assign_type(field, entry);
m = &field->map;
switch (m->opcode) {
case MMIO_PROBE:
- ret = trace_seq_printf(s,
+ trace_seq_printf(s,
"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
secs, usec_rem, m->map_id,
(unsigned long long)m->phys, m->virt, m->len,
0UL, 0);
break;
case MMIO_UNPROBE:
- ret = trace_seq_printf(s,
+ trace_seq_printf(s,
"UNMAP %u.%06lu %d 0x%lx %d\n",
secs, usec_rem, m->map_id, 0UL, 0);
break;
default:
- ret = trace_seq_puts(s, "map what?\n");
+ trace_seq_puts(s, "map what?\n");
break;
}
- if (ret)
- return TRACE_TYPE_HANDLED;
- return TRACE_TYPE_PARTIAL_LINE;
+
+ return trace_handle_return(s);
}
static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
@@ -262,14 +255,11 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
unsigned long long t = ns2usecs(iter->ts);
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned secs = (unsigned long)t;
- int ret;
/* The trailing newline must be in the message. */
- ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t mmio_print_line(struct trace_iterator *iter)
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf()
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (7 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 08/23 v4] tracing: Do not check return values of trace_seq_p*() for mmio tracer Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 15:30 ` Masami Hiramatsu
2014-11-18 0:30 ` Namhyung Kim
2014-11-14 1:12 ` [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values " Steven Rostedt
` (13 subsequent siblings)
22 siblings, 2 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek,
Masami Hiramatsu, Namhyung Kim
[-- Attachment #1: 0009-tracing-probes-Do-not-use-return-value-of-trace_seq_.patch --]
[-- Type: text/plain, Size: 1667 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The functions trace_seq_printf() and friends will soon not have a return
value and will only be a void function. Use trace_seq_has_overflowed()
instead to know if the trace_seq operations succeeded or not.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_probe.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index d4b9fc22cd27..b983b2fd2ca1 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -40,7 +40,8 @@ const char *reserved_field_names[] = {
int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
void *data, void *ent) \
{ \
- return trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
+ trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
+ return !trace_seq_has_overflowed(s); \
} \
const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
@@ -61,10 +62,11 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
int len = *(u32 *)data >> 16;
if (!len)
- return trace_seq_printf(s, " %s=(fault)", name);
+ trace_seq_printf(s, " %s=(fault)", name);
else
- return trace_seq_printf(s, " %s=\"%s\"", name,
- (const char *)get_loc_data(data, ent));
+ trace_seq_printf(s, " %s=\"%s\"", name,
+ (const char *)get_loc_data(data, ent));
+ return !trace_seq_has_overflowed(s);
}
NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf()
2014-11-14 1:12 ` [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf() Steven Rostedt
@ 2014-11-14 15:30 ` Masami Hiramatsu
2014-11-18 0:30 ` Namhyung Kim
1 sibling, 0 replies; 58+ messages in thread
From: Masami Hiramatsu @ 2014-11-14 15:30 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Namhyung Kim
(2014/11/14 10:12), Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The functions trace_seq_printf() and friends will soon not have a return
> value and will only be a void function. Use trace_seq_has_overflowed()
> instead to know if the trace_seq operations succeeded or not.
>
OK, Looks good to me.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace_probe.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index d4b9fc22cd27..b983b2fd2ca1 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -40,7 +40,8 @@ const char *reserved_field_names[] = {
> int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
> void *data, void *ent) \
> { \
> - return trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
> + trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
> + return !trace_seq_has_overflowed(s); \
> } \
> const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
> NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
> @@ -61,10 +62,11 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
> int len = *(u32 *)data >> 16;
>
> if (!len)
> - return trace_seq_printf(s, " %s=(fault)", name);
> + trace_seq_printf(s, " %s=(fault)", name);
> else
> - return trace_seq_printf(s, " %s=\"%s\"", name,
> - (const char *)get_loc_data(data, ent));
> + trace_seq_printf(s, " %s=\"%s\"", name,
> + (const char *)get_loc_data(data, ent));
> + return !trace_seq_has_overflowed(s);
> }
> NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf()
2014-11-14 1:12 ` [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf() Steven Rostedt
2014-11-14 15:30 ` Masami Hiramatsu
@ 2014-11-18 0:30 ` Namhyung Kim
1 sibling, 0 replies; 58+ messages in thread
From: Namhyung Kim @ 2014-11-18 0:30 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Masami Hiramatsu
Hi Steve,
On Thu, 13 Nov 2014 20:12:53 -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The functions trace_seq_printf() and friends will soon not have a return
> value and will only be a void function. Use trace_seq_has_overflowed()
> instead to know if the trace_seq operations succeeded or not.
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace_probe.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index d4b9fc22cd27..b983b2fd2ca1 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -40,7 +40,8 @@ const char *reserved_field_names[] = {
> int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
> void *data, void *ent) \
> { \
> - return trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
> + trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
> + return !trace_seq_has_overflowed(s); \
At first, I wondered why you used this instead of trace_handle_return()
but I found out that it's only used for checking loop break so I'm okay
with this.
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> } \
> const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
> NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
> @@ -61,10 +62,11 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
> int len = *(u32 *)data >> 16;
>
> if (!len)
> - return trace_seq_printf(s, " %s=(fault)", name);
> + trace_seq_printf(s, " %s=(fault)", name);
> else
> - return trace_seq_printf(s, " %s=\"%s\"", name,
> - (const char *)get_loc_data(data, ent));
> + trace_seq_printf(s, " %s=\"%s\"", name,
> + (const char *)get_loc_data(data, ent));
> + return !trace_seq_has_overflowed(s);
> }
> NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (8 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 09/23 v4] tracing/probes: Do not use return value of trace_seq_printf() Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 5:23 ` Srikar Dronamraju
2014-11-14 15:35 ` Masami Hiramatsu
2014-11-14 1:12 ` [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing Steven Rostedt
` (12 subsequent siblings)
22 siblings, 2 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek,
Masami Hiramatsu, Namhyung Kim, Srikar Dronamraju
[-- Attachment #1: 0010-tracing-uprobes-Do-not-use-return-values-of-trace_se.patch --]
[-- Type: text/plain, Size: 2006 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The functions trace_seq_printf() and friends will soon no longer have
return values. Using trace_seq_has_overflowed() and trace_handle_return()
should be used instead.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_uprobe.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 33ff6a24b802..bd6007b13b52 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -852,31 +852,26 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
tu = container_of(event, struct trace_uprobe, tp.call.event);
if (is_ret_probe(tu)) {
- if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
- ftrace_event_name(&tu->tp.call),
- entry->vaddr[1], entry->vaddr[0]))
- goto partial;
+ trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
+ ftrace_event_name(&tu->tp.call),
+ entry->vaddr[1], entry->vaddr[0]);
data = DATAOF_TRACE_ENTRY(entry, true);
} else {
- if (!trace_seq_printf(s, "%s: (0x%lx)",
- ftrace_event_name(&tu->tp.call),
- entry->vaddr[0]))
- goto partial;
+ trace_seq_printf(s, "%s: (0x%lx)",
+ ftrace_event_name(&tu->tp.call),
+ entry->vaddr[0]);
data = DATAOF_TRACE_ENTRY(entry, false);
}
for (i = 0; i < tu->tp.nr_args; i++) {
struct probe_arg *parg = &tu->tp.args[i];
- if (!parg->type->print(s, parg->name, data + parg->offset, entry))
- goto partial;
+ parg->type->print(s, parg->name, data + parg->offset, entry);
}
- if (trace_seq_puts(s, "\n"))
- return TRACE_TYPE_HANDLED;
+ trace_seq_puts(s, "\n");
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_handle_return(s);
}
typedef bool (*filter_func_t)(struct uprobe_consumer *self,
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 1:12 ` [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values " Steven Rostedt
@ 2014-11-14 5:23 ` Srikar Dronamraju
2014-11-14 15:35 ` Masami Hiramatsu
1 sibling, 0 replies; 58+ messages in thread
From: Srikar Dronamraju @ 2014-11-14 5:23 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Masami Hiramatsu, Namhyung Kim
* Steven Rostedt <rostedt@goodmis.org> [2014-11-13 20:12:54]:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The functions trace_seq_printf() and friends will soon no longer have
> return values. Using trace_seq_has_overflowed() and trace_handle_return()
> should be used instead.
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Looks good to me.
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
--
Thanks and Regards
Srikar Dronamraju
^ permalink raw reply [flat|nested] 58+ messages in thread
* Re: [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 1:12 ` [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values " Steven Rostedt
2014-11-14 5:23 ` Srikar Dronamraju
@ 2014-11-14 15:35 ` Masami Hiramatsu
2014-11-14 15:37 ` Steven Rostedt
1 sibling, 1 reply; 58+ messages in thread
From: Masami Hiramatsu @ 2014-11-14 15:35 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Namhyung Kim, Srikar Dronamraju
(2014/11/14 10:12), Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The functions trace_seq_printf() and friends will soon no longer have
> return values. Using trace_seq_has_overflowed() and trace_handle_return()
> should be used instead.
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace_uprobe.c | 23 +++++++++--------------
> 1 file changed, 9 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 33ff6a24b802..bd6007b13b52 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -852,31 +852,26 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
> tu = container_of(event, struct trace_uprobe, tp.call.event);
>
> if (is_ret_probe(tu)) {
> - if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
> - ftrace_event_name(&tu->tp.call),
> - entry->vaddr[1], entry->vaddr[0]))
> - goto partial;
> + trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
> + ftrace_event_name(&tu->tp.call),
> + entry->vaddr[1], entry->vaddr[0]);
> data = DATAOF_TRACE_ENTRY(entry, true);
> } else {
> - if (!trace_seq_printf(s, "%s: (0x%lx)",
> - ftrace_event_name(&tu->tp.call),
> - entry->vaddr[0]))
> - goto partial;
> + trace_seq_printf(s, "%s: (0x%lx)",
> + ftrace_event_name(&tu->tp.call),
> + entry->vaddr[0]);
> data = DATAOF_TRACE_ENTRY(entry, false);
> }
>
> for (i = 0; i < tu->tp.nr_args; i++) {
> struct probe_arg *parg = &tu->tp.args[i];
>
> - if (!parg->type->print(s, parg->name, data + parg->offset, entry))
> - goto partial;
> + parg->type->print(s, parg->name, data + parg->offset, entry);
In 7/23 you've left loop canceling path, why don't you do same thing here?
Thank you,
> }
>
> - if (trace_seq_puts(s, "\n"))
> - return TRACE_TYPE_HANDLED;
> + trace_seq_puts(s, "\n");
>
> -partial:
> - return TRACE_TYPE_PARTIAL_LINE;
> + return trace_handle_return(s);
> }
>
> typedef bool (*filter_func_t)(struct uprobe_consumer *self,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 15:35 ` Masami Hiramatsu
@ 2014-11-14 15:37 ` Steven Rostedt
2014-11-14 18:14 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 15:37 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Namhyung Kim, Srikar Dronamraju
On Sat, 15 Nov 2014 00:35:15 +0900
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> > for (i = 0; i < tu->tp.nr_args; i++) {
> > struct probe_arg *parg = &tu->tp.args[i];
> >
> > - if (!parg->type->print(s, parg->name, data + parg->offset, entry))
> > - goto partial;
> > + parg->type->print(s, parg->name, data + parg->offset, entry);
>
> In 7/23 you've left loop canceling path, why don't you do same thing here?
While rebasing this series on my latest code, this patch conflicted. I
notice the difference too (just two minutes ago!).
I agree, it should break out still.
Srikar, can I still have your Reviewed-by if I do that?
-- Steve
>
> Thank you,
>
> > }
> >
> > - if (trace_seq_puts(s, "\n"))
> > - return TRACE_TYPE_HANDLED;
> > + trace_seq_puts(s, "\n");
> >
> > -partial:
> > - return TRACE_TYPE_PARTIAL_LINE;
> > + return trace_handle_return(s);
> > }
> >
> > typedef bool (*filter_func_t)(struct uprobe_consumer *self,
>
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 15:37 ` Steven Rostedt
@ 2014-11-14 18:14 ` Steven Rostedt
2014-11-18 0:32 ` Namhyung Kim
0 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 18:14 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek, Namhyung Kim, Srikar Dronamraju
On Fri, 14 Nov 2014 10:37:33 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Sat, 15 Nov 2014 00:35:15 +0900
> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>
> > > for (i = 0; i < tu->tp.nr_args; i++) {
> > > struct probe_arg *parg = &tu->tp.args[i];
> > >
> > > - if (!parg->type->print(s, parg->name, data + parg->offset, entry))
> > > - goto partial;
> > > + parg->type->print(s, parg->name, data + parg->offset, entry);
> >
> > In 7/23 you've left loop canceling path, why don't you do same thing here?
>
> While rebasing this series on my latest code, this patch conflicted. I
> notice the difference too (just two minutes ago!).
>
> I agree, it should break out still.
>
> Srikar, can I still have your Reviewed-by if I do that?
>
Here's the new patch:
-- Steve
>From cd883b4c2d5d68ec598d6c6a3b5dce4dd99a4cc1 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 12 Nov 2014 17:26:57 -0500
Subject: [PATCH] tracing/uprobes: Do not use return values of
trace_seq_printf()
The functions trace_seq_printf() and friends will soon no longer have
return values. Using trace_seq_has_overflowed() and trace_handle_return()
should be used instead.
Link: http://lkml.kernel.org/r/20141114011411.693008134@goodmis.org
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_uprobe.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index e35327c787f7..fd76f8e108ef 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -852,16 +852,14 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
tu = container_of(event, struct trace_uprobe, tp.call.event);
if (is_ret_probe(tu)) {
- if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
- ftrace_event_name(&tu->tp.call),
- entry->vaddr[1], entry->vaddr[0]))
- goto partial;
+ trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
+ ftrace_event_name(&tu->tp.call),
+ entry->vaddr[1], entry->vaddr[0]);
data = DATAOF_TRACE_ENTRY(entry, true);
} else {
- if (!trace_seq_printf(s, "%s: (0x%lx)",
- ftrace_event_name(&tu->tp.call),
- entry->vaddr[0]))
- goto partial;
+ trace_seq_printf(s, "%s: (0x%lx)",
+ ftrace_event_name(&tu->tp.call),
+ entry->vaddr[0]);
data = DATAOF_TRACE_ENTRY(entry, false);
}
@@ -869,14 +867,13 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
struct probe_arg *parg = &tu->tp.args[i];
if (!parg->type->print(s, parg->name, data + parg->offset, entry))
- goto partial;
+ goto out;
}
- if (trace_seq_putc(s, '\n'))
- return TRACE_TYPE_HANDLED;
+ trace_seq_putc(s, '\n');
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ out:
+ return trace_handle_return(s);
}
typedef bool (*filter_func_t)(struct uprobe_consumer *self,
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values of trace_seq_printf()
2014-11-14 18:14 ` Steven Rostedt
@ 2014-11-18 0:32 ` Namhyung Kim
0 siblings, 0 replies; 58+ messages in thread
From: Namhyung Kim @ 2014-11-18 0:32 UTC (permalink / raw)
To: Steven Rostedt
Cc: Masami Hiramatsu, linux-kernel, Ingo Molnar, Andrew Morton,
Jiri Kosina, Petr Mladek, Srikar Dronamraju
On Fri, 14 Nov 2014 13:14:29 -0500, Steven Rostedt wrote:
> Here's the new patch:
>
> -- Steve
>
> From cd883b4c2d5d68ec598d6c6a3b5dce4dd99a4cc1 Mon Sep 17 00:00:00 2001
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> Date: Wed, 12 Nov 2014 17:26:57 -0500
> Subject: [PATCH] tracing/uprobes: Do not use return values of
> trace_seq_printf()
>
> The functions trace_seq_printf() and friends will soon no longer have
> return values. Using trace_seq_has_overflowed() and trace_handle_return()
> should be used instead.
>
> Link: http://lkml.kernel.org/r/20141114011411.693008134@goodmis.org
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> ---
> kernel/trace/trace_uprobe.c | 23 ++++++++++-------------
> 1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index e35327c787f7..fd76f8e108ef 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -852,16 +852,14 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
> tu = container_of(event, struct trace_uprobe, tp.call.event);
>
> if (is_ret_probe(tu)) {
> - if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
> - ftrace_event_name(&tu->tp.call),
> - entry->vaddr[1], entry->vaddr[0]))
> - goto partial;
> + trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
> + ftrace_event_name(&tu->tp.call),
> + entry->vaddr[1], entry->vaddr[0]);
> data = DATAOF_TRACE_ENTRY(entry, true);
> } else {
> - if (!trace_seq_printf(s, "%s: (0x%lx)",
> - ftrace_event_name(&tu->tp.call),
> - entry->vaddr[0]))
> - goto partial;
> + trace_seq_printf(s, "%s: (0x%lx)",
> + ftrace_event_name(&tu->tp.call),
> + entry->vaddr[0]);
> data = DATAOF_TRACE_ENTRY(entry, false);
> }
>
> @@ -869,14 +867,13 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
> struct probe_arg *parg = &tu->tp.args[i];
>
> if (!parg->type->print(s, parg->name, data + parg->offset, entry))
> - goto partial;
> + goto out;
> }
>
> - if (trace_seq_putc(s, '\n'))
> - return TRACE_TYPE_HANDLED;
> + trace_seq_putc(s, '\n');
>
> -partial:
> - return TRACE_TYPE_PARTIAL_LINE;
> + out:
> + return trace_handle_return(s);
> }
>
> typedef bool (*filter_func_t)(struct uprobe_consumer *self,
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (9 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 10/23 v4] tracing/uprobes: Do not use return values " Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-18 0:49 ` Namhyung Kim
2014-11-14 1:12 ` [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions Steven Rostedt
` (11 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0011-tracing-Do-not-use-return-values-of-trace_seq_printf.patch --]
[-- Type: text/plain, Size: 3030 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The functions trace_seq_printf() and friends will not be returning values
soon and will be void functions. To know if they succeeded or not, the
functions trace_seq_has_overflowed() and trace_handle_return() should be
used instead.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_syscalls.c | 43 +++++++++++++++----------------------------
1 file changed, 15 insertions(+), 28 deletions(-)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4dc8b79c5f75..2193e8038681 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
struct trace_entry *ent = iter->ent;
struct syscall_trace_enter *trace;
struct syscall_metadata *entry;
- int i, ret, syscall;
+ int i, syscall;
trace = (typeof(trace))ent;
syscall = trace->nr;
@@ -128,35 +128,24 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
goto end;
}
- ret = trace_seq_printf(s, "%s(", entry->name);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s(", entry->name);
for (i = 0; i < entry->nb_args; i++) {
/* parameter types */
- if (trace_flags & TRACE_ITER_VERBOSE) {
- ret = trace_seq_printf(s, "%s ", entry->types[i]);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (trace_flags & TRACE_ITER_VERBOSE)
+ trace_seq_printf(s, "%s ", entry->types[i]);
+
/* parameter values */
- ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
- trace->args[i],
- i == entry->nb_args - 1 ? "" : ", ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+ trace->args[i],
+ i == entry->nb_args - 1 ? "" : ", ");
}
- ret = trace_seq_putc(s, ')');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
+ trace_seq_putc(s, ')');
end:
- ret = trace_seq_putc(s, '\n');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_putc(s, '\n');
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t
@@ -168,7 +157,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
struct syscall_trace_exit *trace;
int syscall;
struct syscall_metadata *entry;
- int ret;
trace = (typeof(trace))ent;
syscall = trace->nr;
@@ -176,7 +164,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
if (!entry) {
trace_seq_putc(s, '\n');
- return TRACE_TYPE_HANDLED;
+ goto out;
}
if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +172,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
return TRACE_TYPE_UNHANDLED;
}
- ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+ trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
trace->ret);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- return TRACE_TYPE_HANDLED;
+ out:
+ return trace_handle_return(s);
}
extern char *__bad_type_size(void);
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing
2014-11-14 1:12 ` [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing Steven Rostedt
@ 2014-11-18 0:49 ` Namhyung Kim
2014-11-18 2:44 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Namhyung Kim @ 2014-11-18 0:49 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek
On Thu, 13 Nov 2014 20:12:55 -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The functions trace_seq_printf() and friends will not be returning values
> soon and will be void functions. To know if they succeeded or not, the
> functions trace_seq_has_overflowed() and trace_handle_return() should be
> used instead.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> kernel/trace/trace_syscalls.c | 43 +++++++++++++++----------------------------
> 1 file changed, 15 insertions(+), 28 deletions(-)
>
> diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> index 4dc8b79c5f75..2193e8038681 100644
> --- a/kernel/trace/trace_syscalls.c
> +++ b/kernel/trace/trace_syscalls.c
> @@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
> struct trace_entry *ent = iter->ent;
> struct syscall_trace_enter *trace;
> struct syscall_metadata *entry;
> - int i, ret, syscall;
> + int i, syscall;
>
> trace = (typeof(trace))ent;
> syscall = trace->nr;
> @@ -128,35 +128,24 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
> goto end;
> }
>
> - ret = trace_seq_printf(s, "%s(", entry->name);
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> + trace_seq_printf(s, "%s(", entry->name);
>
> for (i = 0; i < entry->nb_args; i++) {
if (trace_seq_has_overflowed())
goto end;
?
Thanks,
Namhyung
> /* parameter types */
> - if (trace_flags & TRACE_ITER_VERBOSE) {
> - ret = trace_seq_printf(s, "%s ", entry->types[i]);
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> - }
> + if (trace_flags & TRACE_ITER_VERBOSE)
> + trace_seq_printf(s, "%s ", entry->types[i]);
> +
> /* parameter values */
> - ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
> - trace->args[i],
> - i == entry->nb_args - 1 ? "" : ", ");
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> + trace_seq_printf(s, "%s: %lx%s", entry->args[i],
> + trace->args[i],
> + i == entry->nb_args - 1 ? "" : ", ");
> }
>
> - ret = trace_seq_putc(s, ')');
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> -
> + trace_seq_putc(s, ')');
> end:
> - ret = trace_seq_putc(s, '\n');
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> + trace_seq_putc(s, '\n');
>
> - return TRACE_TYPE_HANDLED;
> + return trace_handle_return(s);
> }
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing
2014-11-18 0:49 ` Namhyung Kim
@ 2014-11-18 2:44 ` Steven Rostedt
2014-11-18 3:04 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-18 2:44 UTC (permalink / raw)
To: Namhyung Kim
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek
On Tue, 18 Nov 2014 09:49:12 +0900
Namhyung Kim <namhyung@kernel.org> wrote:
> On Thu, 13 Nov 2014 20:12:55 -0500, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > The functions trace_seq_printf() and friends will not be returning values
> > soon and will be void functions. To know if they succeeded or not, the
> > functions trace_seq_has_overflowed() and trace_handle_return() should be
> > used instead.
> >
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > kernel/trace/trace_syscalls.c | 43 +++++++++++++++----------------------------
> > 1 file changed, 15 insertions(+), 28 deletions(-)
> >
> > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> > index 4dc8b79c5f75..2193e8038681 100644
> > --- a/kernel/trace/trace_syscalls.c
> > +++ b/kernel/trace/trace_syscalls.c
> > @@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
> > struct trace_entry *ent = iter->ent;
> > struct syscall_trace_enter *trace;
> > struct syscall_metadata *entry;
> > - int i, ret, syscall;
> > + int i, syscall;
> >
> > trace = (typeof(trace))ent;
> > syscall = trace->nr;
> > @@ -128,35 +128,24 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
> > goto end;
> > }
> >
> > - ret = trace_seq_printf(s, "%s(", entry->name);
> > - if (!ret)
> > - return TRACE_TYPE_PARTIAL_LINE;
> > + trace_seq_printf(s, "%s(", entry->name);
> >
> > for (i = 0; i < entry->nb_args; i++) {
>
> if (trace_seq_has_overflowed())
> goto end;
> ?
Yeah, I guess I can do that.
Oh well, so much for not needing to post the first 13 patches again ;-)
-- Steve
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing
2014-11-18 2:44 ` Steven Rostedt
@ 2014-11-18 3:04 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-18 3:04 UTC (permalink / raw)
To: Namhyung Kim
Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina,
Petr Mladek
On Mon, 17 Nov 2014 21:44:11 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Tue, 18 Nov 2014 09:49:12 +0900
> Namhyung Kim <namhyung@kernel.org> wrote:
>
> > > - ret = trace_seq_printf(s, "%s(", entry->name);
> > > - if (!ret)
> > > - return TRACE_TYPE_PARTIAL_LINE;
> > > + trace_seq_printf(s, "%s(", entry->name);
> > >
> > > for (i = 0; i < entry->nb_args; i++) {
> >
> > if (trace_seq_has_overflowed())
> > goto end;
> > ?
>
> Yeah, I guess I can do that.
>
Here's the update:
-- Steve
>From 17845179b46f3e8b849d06a9a0069fd0a085e666 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 12 Nov 2014 17:41:33 -0500
Subject: [PATCH] tracing: Do not use return values of trace_seq_printf() in
syscall tracing
The functions trace_seq_printf() and friends will not be returning values
soon and will be void functions. To know if they succeeded or not, the
functions trace_seq_has_overflowed() and trace_handle_return() should be
used instead.
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_syscalls.c | 47 +++++++++++++++++--------------------------
1 file changed, 19 insertions(+), 28 deletions(-)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4dc8b79c5f75..a72f3d8d813e 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
struct trace_entry *ent = iter->ent;
struct syscall_trace_enter *trace;
struct syscall_metadata *entry;
- int i, ret, syscall;
+ int i, syscall;
trace = (typeof(trace))ent;
syscall = trace->nr;
@@ -128,35 +128,28 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
goto end;
}
- ret = trace_seq_printf(s, "%s(", entry->name);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s(", entry->name);
for (i = 0; i < entry->nb_args; i++) {
+
+ if (trace_seq_has_overflowed(s))
+ goto end;
+
/* parameter types */
- if (trace_flags & TRACE_ITER_VERBOSE) {
- ret = trace_seq_printf(s, "%s ", entry->types[i]);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- }
+ if (trace_flags & TRACE_ITER_VERBOSE)
+ trace_seq_printf(s, "%s ", entry->types[i]);
+
/* parameter values */
- ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
- trace->args[i],
- i == entry->nb_args - 1 ? "" : ", ");
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+ trace->args[i],
+ i == entry->nb_args - 1 ? "" : ", ");
}
- ret = trace_seq_putc(s, ')');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
+ trace_seq_putc(s, ')');
end:
- ret = trace_seq_putc(s, '\n');
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ trace_seq_putc(s, '\n');
- return TRACE_TYPE_HANDLED;
+ return trace_handle_return(s);
}
static enum print_line_t
@@ -168,7 +161,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
struct syscall_trace_exit *trace;
int syscall;
struct syscall_metadata *entry;
- int ret;
trace = (typeof(trace))ent;
syscall = trace->nr;
@@ -176,7 +168,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
if (!entry) {
trace_seq_putc(s, '\n');
- return TRACE_TYPE_HANDLED;
+ goto out;
}
if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +176,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
return TRACE_TYPE_UNHANDLED;
}
- ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+ trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
trace->ret);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- return TRACE_TYPE_HANDLED;
+ out:
+ return trace_handle_return(s);
}
extern char *__bad_type_size(void);
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (10 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 11/23 v4] tracing: Do not use return values of trace_seq_printf() in syscall tracing Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 13:17 ` Petr Mladek
2014-11-14 1:12 ` [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq Steven Rostedt
` (10 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0012-tracing-Remove-return-values-of-most-trace_seq_-func.patch --]
[-- Type: text/plain, Size: 10526 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The trace_seq_printf() and friends are used to store strings into a buffer
that can be passed around from function to function. If the trace_seq buffer
fills up, it will not print any more. The return values were somewhat
inconsistant and using trace_seq_has_overflowed() was a better way to know
if the write to the trace_seq buffer succeeded or not.
Now that all users have removed reading the return value of the printf()
type functions, they can safely return void and keep future users of them
from reading the inconsistent values as well.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/trace_seq.h | 37 +++++++++------------
kernel/trace/trace_seq.c | 84 +++++++++++++----------------------------------
2 files changed, 37 insertions(+), 84 deletions(-)
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 07eda413dfcf..db8a73224f1a 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -57,40 +57,37 @@ static inline bool trace_seq_has_overflowed(struct trace_seq *s)
*/
#ifdef CONFIG_TRACING
extern __printf(2, 3)
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
-extern int
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
+extern void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
int cnt);
-extern int trace_seq_puts(struct trace_seq *s, const char *str);
-extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
-extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
-extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+extern void trace_seq_puts(struct trace_seq *s, const char *str);
+extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
+extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len);
extern int trace_seq_path(struct trace_seq *s, const struct path *path);
-extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits);
#else /* CONFIG_TRACING */
-static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- return 0;
}
static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
@@ -102,23 +99,19 @@ static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
{
return 0;
}
-static inline int trace_seq_puts(struct trace_seq *s, const char *str)
+static inline void trace_seq_puts(struct trace_seq *s, const char *str)
{
- return 0;
}
-static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
+static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
- return 0;
}
-static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- return 0;
}
static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
{
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index b100994a17fe..e54c0a1fb3f0 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -69,20 +69,15 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
* trace_seq_printf() is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
- *
- * Returns 1 if we successfully written all the contents to
- * the buffer.
- * Returns 0 if we the length to write is bigger than the
- * reserved buffer space. In this case, nothing gets written.
*/
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
va_list ap;
int ret;
if (s->full || !len)
- return 0;
+ return;
va_start(ap, fmt);
ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
@@ -91,12 +86,10 @@ int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -107,25 +100,18 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
* @nmaskbits: The number of bits that are valid in @maskp
*
* Writes a ASCII representation of a bitmask string into @s.
- *
- * Returns 1 if we successfully written all the contents to
- * the buffer.
- * Returns 0 if we the length to write is bigger than the
- * reserved buffer space. In this case, nothing gets written.
*/
-int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
s->len += ret;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);
@@ -139,28 +125,24 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = vsnprintf(s->buffer + s->len, len, fmt, args);
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);
@@ -178,28 +160,24 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*
* This function will take the format and the binary array and finish
* the conversion into the ASCII string within the buffer.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);
@@ -212,25 +190,21 @@ EXPORT_SYMBOL_GPL(trace_seq_bprintf);
* copy to user routines. This function records a simple string
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_puts(struct trace_seq *s, const char *str)
+void trace_seq_puts(struct trace_seq *s, const char *str)
{
unsigned int len = strlen(str);
if (s->full)
- return 0;
+ return;
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
- return 0;
+ return;
}
memcpy(s->buffer + s->len, str, len);
s->len += len;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_puts);
@@ -243,22 +217,18 @@ EXPORT_SYMBOL_GPL(trace_seq_puts);
* copy to user routines. This function records a simple charater
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putc(struct trace_seq *s, unsigned char c)
+void trace_seq_putc(struct trace_seq *s, unsigned char c)
{
if (s->full)
- return 0;
+ return;
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
- return 0;
+ return;
}
s->buffer[s->len++] = c;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_putc);
@@ -271,23 +241,19 @@ EXPORT_SYMBOL_GPL(trace_seq_putc);
* There may be cases where raw memory needs to be written into the
* buffer and a strcpy() would not work. Using this function allows
* for such cases.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
if (s->full)
- return 0;
+ return;
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
- return 0;
+ return;
}
memcpy(s->buffer + s->len, mem, len);
s->len += len;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);
@@ -303,20 +269,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
* This is similar to trace_seq_putmem() except instead of just copying the
* raw memory into the buffer it writes its ASCII representation of it
* in hex characters.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
unsigned char hex[HEX_CHARS];
const unsigned char *data = mem;
unsigned int start_len;
int i, j;
- int cnt = 0;
if (s->full)
- return 0;
+ return;
while (len) {
start_len = min(len, HEX_CHARS - 1);
@@ -334,10 +297,7 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
/* j increments twice per loop */
len -= j / 2;
hex[j++] = ' ';
-
- cnt += trace_seq_putmem(s, hex, j);
}
- return cnt;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions
2014-11-14 1:12 ` [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions Steven Rostedt
@ 2014-11-14 13:17 ` Petr Mladek
2014-11-14 14:53 ` Steven Rostedt
2014-11-14 17:09 ` Steven Rostedt
0 siblings, 2 replies; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 13:17 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:12:56, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> The trace_seq_printf() and friends are used to store strings into a buffer
> that can be passed around from function to function. If the trace_seq buffer
> fills up, it will not print any more. The return values were somewhat
> inconsistant and using trace_seq_has_overflowed() was a better way to know
> if the write to the trace_seq buffer succeeded or not.
>
> Now that all users have removed reading the return value of the printf()
> type functions, they can safely return void and keep future users of them
> from reading the inconsistent values as well.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> include/linux/trace_seq.h | 37 +++++++++------------
> kernel/trace/trace_seq.c | 84 +++++++++++++----------------------------------
> 2 files changed, 37 insertions(+), 84 deletions(-)
[...]
> diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
> index b100994a17fe..e54c0a1fb3f0 100644
> --- a/kernel/trace/trace_seq.c
> +++ b/kernel/trace/trace_seq.c
[...]
> @@ -303,20 +269,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
> * This is similar to trace_seq_putmem() except instead of just copying the
> * raw memory into the buffer it writes its ASCII representation of it
> * in hex characters.
> - *
> - * Returns how much it wrote to the buffer.
> */
> -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> +void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> unsigned int len)
> {
> unsigned char hex[HEX_CHARS];
> const unsigned char *data = mem;
> unsigned int start_len;
> int i, j;
> - int cnt = 0;
>
> if (s->full)
> - return 0;
> + return;
>
> while (len) {
> start_len = min(len, HEX_CHARS - 1);
> @@ -334,10 +297,7 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> /* j increments twice per loop */
> len -= j / 2;
> hex[j++] = ' ';
> -
> - cnt += trace_seq_putmem(s, hex, j);
trace_seq_putmem(s, hex, j); should stay ;-)
Best Regards,
Petr
> }
> - return cnt;
> }
> EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
>
> --
> 2.1.1
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions
2014-11-14 13:17 ` Petr Mladek
@ 2014-11-14 14:53 ` Steven Rostedt
2014-11-14 16:21 ` Steven Rostedt
2014-11-14 17:09 ` Steven Rostedt
1 sibling, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 14:53 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 14:17:28 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> > -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> > +void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> > unsigned int len)
> > {
> > unsigned char hex[HEX_CHARS];
> > const unsigned char *data = mem;
> > unsigned int start_len;
> > int i, j;
> > - int cnt = 0;
> >
> > if (s->full)
> > - return 0;
> > + return;
> >
> > while (len) {
> > start_len = min(len, HEX_CHARS - 1);
> > @@ -334,10 +297,7 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> > /* j increments twice per loop */
> > len -= j / 2;
> > hex[j++] = ' ';
> > -
> > - cnt += trace_seq_putmem(s, hex, j);
>
> trace_seq_putmem(s, hex, j); should stay ;-)
Ouch! Looks like I got a little happy with the delete line key stroke.
Good catch!
Thanks,
-- Steve
>
> Best Regards,
> Petr
>
> > }
> > - return cnt;
> > }
> > EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
> >
> > --
> > 2.1.1
> >
> >
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions
2014-11-14 14:53 ` Steven Rostedt
@ 2014-11-14 16:21 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 16:21 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 09:53:39 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> > > @@ -334,10 +297,7 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> > > /* j increments twice per loop */
> > > len -= j / 2;
> > > hex[j++] = ' ';
> > > -
> > > - cnt += trace_seq_putmem(s, hex, j);
> >
> > trace_seq_putmem(s, hex, j); should stay ;-)
>
> Ouch! Looks like I got a little happy with the delete line key stroke.
>
> Good catch!
>
And in the end it really didn't matter, as the patch "tracing: Create
seq_buf layer in trace_seq" took all this out.
I'll still update the patch for correctness.
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 58+ messages in thread
* Re: [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions
2014-11-14 13:17 ` Petr Mladek
2014-11-14 14:53 ` Steven Rostedt
@ 2014-11-14 17:09 ` Steven Rostedt
1 sibling, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:09 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 14:17:28 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> > @@ -334,10 +297,7 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
> > /* j increments twice per loop */
> > len -= j / 2;
> > hex[j++] = ' ';
> > -
> > - cnt += trace_seq_putmem(s, hex, j);
>
> trace_seq_putmem(s, hex, j); should stay ;-)
Here's the new patch:
>From 08223449645f482ee41333d414228da1d46e2095 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 12 Nov 2014 18:07:22 -0500
Subject: [PATCH] tracing: Remove return values of most trace_seq_*() functions
The trace_seq_printf() and friends are used to store strings into a buffer
that can be passed around from function to function. If the trace_seq buffer
fills up, it will not print any more. The return values were somewhat
inconsistant and using trace_seq_has_overflowed() was a better way to know
if the write to the trace_seq buffer succeeded or not.
Now that all users have removed reading the return value of the printf()
type functions, they can safely return void and keep future users of them
from reading the inconsistent values as well.
Link: http://lkml.kernel.org/r/20141114011411.992510720@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/trace_seq.h | 37 +++++++++------------
kernel/trace/trace_seq.c | 84 +++++++++++++----------------------------------
2 files changed, 38 insertions(+), 83 deletions(-)
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 07eda413dfcf..db8a73224f1a 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -57,40 +57,37 @@ static inline bool trace_seq_has_overflowed(struct trace_seq *s)
*/
#ifdef CONFIG_TRACING
extern __printf(2, 3)
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
-extern int
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
+extern void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
int cnt);
-extern int trace_seq_puts(struct trace_seq *s, const char *str);
-extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
-extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
-extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+extern void trace_seq_puts(struct trace_seq *s, const char *str);
+extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
+extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len);
extern int trace_seq_path(struct trace_seq *s, const struct path *path);
-extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits);
#else /* CONFIG_TRACING */
-static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- return 0;
}
static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
@@ -102,23 +99,19 @@ static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
{
return 0;
}
-static inline int trace_seq_puts(struct trace_seq *s, const char *str)
+static inline void trace_seq_puts(struct trace_seq *s, const char *str)
{
- return 0;
}
-static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
+static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
{
- return 0;
}
-static inline int
+static inline void
trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
- return 0;
}
-static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- return 0;
}
static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
{
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index b100994a17fe..fabfa0f190a3 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -69,20 +69,15 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
* trace_seq_printf() is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
- *
- * Returns 1 if we successfully written all the contents to
- * the buffer.
- * Returns 0 if we the length to write is bigger than the
- * reserved buffer space. In this case, nothing gets written.
*/
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
va_list ap;
int ret;
if (s->full || !len)
- return 0;
+ return;
va_start(ap, fmt);
ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
@@ -91,12 +86,10 @@ int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -107,25 +100,18 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
* @nmaskbits: The number of bits that are valid in @maskp
*
* Writes a ASCII representation of a bitmask string into @s.
- *
- * Returns 1 if we successfully written all the contents to
- * the buffer.
- * Returns 0 if we the length to write is bigger than the
- * reserved buffer space. In this case, nothing gets written.
*/
-int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
s->len += ret;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);
@@ -139,28 +125,24 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = vsnprintf(s->buffer + s->len, len, fmt, args);
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);
@@ -178,28 +160,24 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*
* This function will take the format and the binary array and finish
* the conversion into the ASCII string within the buffer.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
unsigned int len = TRACE_SEQ_BUF_LEFT(s);
int ret;
if (s->full || !len)
- return 0;
+ return;
ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
- return 0;
+ return;
}
s->len += ret;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);
@@ -212,25 +190,21 @@ EXPORT_SYMBOL_GPL(trace_seq_bprintf);
* copy to user routines. This function records a simple string
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_puts(struct trace_seq *s, const char *str)
+void trace_seq_puts(struct trace_seq *s, const char *str)
{
unsigned int len = strlen(str);
if (s->full)
- return 0;
+ return;
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
- return 0;
+ return;
}
memcpy(s->buffer + s->len, str, len);
s->len += len;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_puts);
@@ -243,22 +217,18 @@ EXPORT_SYMBOL_GPL(trace_seq_puts);
* copy to user routines. This function records a simple charater
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putc(struct trace_seq *s, unsigned char c)
+void trace_seq_putc(struct trace_seq *s, unsigned char c)
{
if (s->full)
- return 0;
+ return;
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
- return 0;
+ return;
}
s->buffer[s->len++] = c;
-
- return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_putc);
@@ -271,23 +241,19 @@ EXPORT_SYMBOL_GPL(trace_seq_putc);
* There may be cases where raw memory needs to be written into the
* buffer and a strcpy() would not work. Using this function allows
* for such cases.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
if (s->full)
- return 0;
+ return;
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
- return 0;
+ return;
}
memcpy(s->buffer + s->len, mem, len);
s->len += len;
-
- return len;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);
@@ -303,20 +269,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
* This is similar to trace_seq_putmem() except instead of just copying the
* raw memory into the buffer it writes its ASCII representation of it
* in hex characters.
- *
- * Returns how much it wrote to the buffer.
*/
-int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
unsigned char hex[HEX_CHARS];
const unsigned char *data = mem;
unsigned int start_len;
int i, j;
- int cnt = 0;
if (s->full)
- return 0;
+ return;
while (len) {
start_len = min(len, HEX_CHARS - 1);
@@ -335,9 +298,8 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
len -= j / 2;
hex[j++] = ' ';
- cnt += trace_seq_putmem(s, hex, j);
+ trace_seq_putmem(s, hex, j);
}
- return cnt;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (11 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 12/23 v4] tracing: Remove return values of most trace_seq_*() functions Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 16:26 ` Petr Mladek
2014-11-14 1:12 ` [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path() Steven Rostedt
` (9 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0013-tracing-Create-seq_buf-layer-in-trace_seq.patch --]
[-- Type: text/plain, Size: 26464 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Create a seq_buf layer that trace_seq sits on. The seq_buf will not
be limited to page size. This will allow other usages of seq_buf
instead of a hard set PAGE_SIZE one that trace_seq has.
Link: http://lkml.kernel.org/r/20141104160221.864997179@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 81 +++++++++
include/linux/trace_seq.h | 12 +-
kernel/trace/Makefile | 1 +
kernel/trace/seq_buf.c | 341 +++++++++++++++++++++++++++++++++++
kernel/trace/trace.c | 39 ++--
kernel/trace/trace_events.c | 6 +-
kernel/trace/trace_functions_graph.c | 6 +-
kernel/trace/trace_seq.c | 172 +++++++++---------
8 files changed, 538 insertions(+), 120 deletions(-)
create mode 100644 include/linux/seq_buf.h
create mode 100644 kernel/trace/seq_buf.c
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
new file mode 100644
index 000000000000..4f7a96a9d71a
--- /dev/null
+++ b/include/linux/seq_buf.h
@@ -0,0 +1,81 @@
+#ifndef _LINUX_SEQ_BUF_H
+#define _LINUX_SEQ_BUF_H
+
+#include <linux/fs.h>
+
+/*
+ * Trace sequences are used to allow a function to call several other functions
+ * to create a string of data to use.
+ */
+
+/**
+ * seq_buf - seq buffer structure
+ * @buffer: pointer to the buffer
+ * @size: size of the buffer
+ * @len: the amount of data inside the buffer
+ * @readpos: The next position to read in the buffer.
+ */
+struct seq_buf {
+ unsigned char *buffer;
+ unsigned int size;
+ unsigned int len;
+ unsigned int readpos;
+};
+
+static inline void
+seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
+{
+ s->buffer = buf;
+ s->size = size;
+ s->len = 0;
+ s->readpos = 0;
+}
+
+/*
+ * seq_buf have a buffer that might overflow. When this happens
+ * the len and size are set to be equal.
+ */
+static inline bool
+seq_buf_has_overflowed(struct seq_buf *s)
+{
+ return s->len == s->size;
+}
+
+static inline void
+seq_buf_set_overflow(struct seq_buf *s)
+{
+ s->len = s->size;
+}
+
+/*
+ * How much buffer is left on the seq_buf?
+ */
+static inline unsigned int
+seq_buf_buffer_left(struct seq_buf *s)
+{
+ if (seq_buf_has_overflowed(s))
+ return 0;
+
+ return (s->size - 1) - s->len;
+}
+
+extern __printf(2, 3)
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
+extern __printf(2, 0)
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
+extern int
+seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
+extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
+extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
+ int cnt);
+extern int seq_buf_puts(struct seq_buf *s, const char *str);
+extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
+extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
+extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len);
+extern int seq_buf_path(struct seq_buf *s, const struct path *path);
+
+extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits);
+
+#endif /* _LINUX_SEQ_BUF_H */
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index db8a73224f1a..85d37106be3d 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H
-#include <linux/fs.h>
+#include <linux/seq_buf.h>
#include <asm/page.h>
@@ -12,16 +12,14 @@
struct trace_seq {
unsigned char buffer[PAGE_SIZE];
- unsigned int len;
- unsigned int readpos;
+ struct seq_buf seq;
int full;
};
static inline void
trace_seq_init(struct trace_seq *s)
{
- s->len = 0;
- s->readpos = 0;
+ seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
s->full = 0;
}
@@ -37,7 +35,7 @@ trace_seq_init(struct trace_seq *s)
static inline unsigned char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
- return s->buffer + s->len;
+ return s->buffer + s->seq.len;
}
/**
@@ -49,7 +47,7 @@ trace_seq_buffer_ptr(struct trace_seq *s)
*/
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
- return s->full || s->len > PAGE_SIZE - 1;
+ return s->full || seq_buf_has_overflowed(&s->seq);
}
/*
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 67d6369ddf83..edc98c72a634 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
+obj-$(CONFIG_TRACING) += seq_buf.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
new file mode 100644
index 000000000000..e9a7861595d2
--- /dev/null
+++ b/kernel/trace/seq_buf.c
@@ -0,0 +1,341 @@
+/*
+ * seq_buf.c
+ *
+ * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The seq_buf is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the seq_buf must be initialized with seq_buf_init().
+ * This will set up the counters within the descriptor. You can call
+ * seq_buf_init() more than once to reset the seq_buf to start
+ * from scratch.
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/seq_buf.h>
+
+/* How much buffer is written? */
+#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
+
+/**
+ * seq_buf_print_seq - move the contents of seq_buf into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the seq_buf descriptor that is the source.
+ *
+ * Returns zero on success, non zero otherwise
+ */
+int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
+{
+ unsigned int len = SEQ_BUF_USED(s);
+
+ return seq_write(m, s->buffer, len);
+}
+
+/**
+ * seq_buf_vprintf - sequence printing of information.
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ * @args: va_list of arguments from a printf() type function
+ *
+ * Writes a vnprintf() format into the sequencce buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
+{
+ int len;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
+ if (s->len + len < s->size) {
+ s->len += len;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_printf - sequence printing of information
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ *
+ * Writes a printf() format into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = seq_buf_vprintf(s, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
+/**
+ * seq_buf_bitmask - write a bitmask array in its ASCII representation
+ * @s: seq_buf descriptor
+ * @maskp: points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits: The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ /*
+ * The last byte of the buffer is used to determine if we
+ * overflowed or not.
+ */
+ if (len > 1) {
+ ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
+ if (ret < len) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_bprintf - Write the printf string from binary arguments
+ * @s: seq_buf descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ if (s->len + ret < s->size) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_puts - sequence printing of simple string
+ * @s: seq_buf descriptor
+ * @str: simple string to record
+ *
+ * Copy a simple string into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_puts(struct seq_buf *s, const char *str)
+{
+ unsigned int len = strlen(str);
+
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, str, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putc - sequence printing of simple character
+ * @s: seq_buf descriptor
+ * @c: simple character to record
+ *
+ * Copy a single character into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putc(struct seq_buf *s, unsigned char c)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + 1 < s->size) {
+ s->buffer[s->len++] = c;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putmem - write raw data into the sequenc buffer
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, mem, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+#define MAX_MEMHEX_BYTES 8U
+#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
+
+/**
+ * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to seq_buf_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len)
+{
+ unsigned char hex[HEX_CHARS];
+ const unsigned char *data = mem;
+ unsigned int start_len;
+ int i, j;
+
+ WARN_ON(s->size == 0);
+
+ while (len) {
+ start_len = min(len, HEX_CHARS - 1);
+#ifdef __BIG_ENDIAN
+ for (i = 0, j = 0; i < start_len; i++) {
+#else
+ for (i = start_len-1, j = 0; i >= 0; i--) {
+#endif
+ hex[j++] = hex_asc_hi(data[i]);
+ hex[j++] = hex_asc_lo(data[i]);
+ }
+ if (WARN_ON_ONCE(j == 0 || j/2 > len))
+ break;
+
+ /* j increments twice per loop */
+ len -= j / 2;
+ hex[j++] = ' ';
+
+ seq_buf_putmem(s, hex, j);
+ if (seq_buf_has_overflowed(s))
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * seq_buf_path - copy a path into the sequence buffer
+ * @s: seq_buf descriptor
+ * @path: path to write into the sequence buffer.
+ *
+ * Write a path name into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_path(struct seq_buf *s, const struct path *path)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ unsigned char *p;
+
+ WARN_ON(s->size == 0);
+
+ p = d_path(path, s->buffer + s->len, len);
+ if (!IS_ERR(p)) {
+ p = mangle_path(s->buffer + s->len, p, "\n");
+ if (p) {
+ s->len = p - s->buffer;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_to_user - copy the squence buffer to user space
+ * @s: seq_buf descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequence (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
+{
+ int len;
+ int ret;
+
+ if (!cnt)
+ return 0;
+
+ if (s->len <= s->readpos)
+ return -EBUSY;
+
+ len = s->len - s->readpos;
+ if (cnt > len)
+ cnt = len;
+ ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+ if (ret == cnt)
+ return -EFAULT;
+
+ cnt -= ret;
+
+ s->readpos += cnt;
+ return cnt;
+}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f5a435a6e8fb..dd43a0d3843a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -938,19 +938,20 @@ out:
return ret;
}
+/* TODO add a seq_buf_to_buffer() */
static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
- if (s->len <= s->readpos)
+ if (s->seq.len <= s->seq.readpos)
return -EBUSY;
- len = s->len - s->readpos;
+ len = s->seq.len - s->seq.readpos;
if (cnt > len)
cnt = len;
- memcpy(buf, s->buffer + s->readpos, cnt);
+ memcpy(buf, s->buffer + s->seq.readpos, cnt);
- s->readpos += cnt;
+ s->seq.readpos += cnt;
return cnt;
}
@@ -4314,6 +4315,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
goto out;
}
+ trace_seq_init(&iter->seq);
+
/*
* We make a copy of the current tracer to avoid concurrent
* changes on it while we are reading.
@@ -4510,18 +4513,18 @@ waitagain:
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
- int len = iter->seq.len;
+ int len = iter->seq.seq.len;
ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
- iter->seq.len = len;
+ iter->seq.seq.len = len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
- if (iter->seq.len >= cnt)
+ if (iter->seq.seq.len >= cnt)
break;
/*
@@ -4537,7 +4540,7 @@ waitagain:
/* Now copy what we have to the user */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
- if (iter->seq.readpos >= iter->seq.len)
+ if (iter->seq.seq.readpos >= iter->seq.seq.len)
trace_seq_init(&iter->seq);
/*
@@ -4575,16 +4578,16 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
- count = iter->seq.len;
+ count = iter->seq.seq.len;
ret = print_trace_line(iter);
- count = iter->seq.len - count;
+ count = iter->seq.seq.len - count;
if (rem < count) {
rem = 0;
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}
@@ -4665,13 +4668,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
/* Copy the data into the page, so we can start over. */
ret = trace_seq_to_buffer(&iter->seq,
page_address(spd.pages[i]),
- iter->seq.len);
+ iter->seq.seq.len);
if (ret < 0) {
__free_page(spd.pages[i]);
break;
}
spd.partial[i].offset = 0;
- spd.partial[i].len = iter->seq.len;
+ spd.partial[i].len = iter->seq.seq.len;
trace_seq_init(&iter->seq);
}
@@ -5672,7 +5675,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "read events: %ld\n", cnt);
- count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
+ count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -6635,11 +6638,11 @@ void
trace_printk_seq(struct trace_seq *s)
{
/* Probably should print a warning here. */
- if (s->len >= TRACE_MAX_PRINT)
- s->len = TRACE_MAX_PRINT;
+ if (s->seq.len >= TRACE_MAX_PRINT)
+ s->seq.len = TRACE_MAX_PRINT;
/* should be zero ended, but we are paranoid. */
- s->buffer[s->len] = 0;
+ s->buffer[s->seq.len] = 0;
printk(KERN_TRACE "%s", s->buffer);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 0cc51edde3a8..33525bf6cbf5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1044,7 +1044,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
mutex_unlock(&event_mutex);
if (file)
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -1210,7 +1210,7 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);
print_subsystem_event_filter(system, s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -1265,7 +1265,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
trace_seq_init(s);
func(s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 477a7c65cf08..19d6145f73ed 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1149,9 +1149,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
}
/* Strip ending newline */
- if (s->buffer[s->len - 1] == '\n') {
- s->buffer[s->len - 1] = '\0';
- s->len--;
+ if (s->buffer[s->seq.len - 1] == '\n') {
+ s->buffer[s->seq.len - 1] = '\0';
+ s->seq.len--;
}
trace_seq_puts(s, " */\n");
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index e54c0a1fb3f0..3c63b619d6b7 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -27,10 +27,19 @@
#include <linux/trace_seq.h>
/* How much buffer is left on the trace_seq? */
-#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len)
+#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1))
+#define TRACE_SEQ_BUF_USED(s) min((s)->seq.len, (unsigned int)(PAGE_SIZE - 1))
+
+/*
+ * trace_seq should work with being initialized with 0s.
+ */
+static inline void __trace_seq_init(struct trace_seq *s)
+{
+ if (unlikely(!s->seq.size))
+ trace_seq_init(s);
+}
/**
* trace_print_seq - move the contents of trace_seq into a seq_file
@@ -43,10 +52,11 @@
*/
int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
- unsigned int len = TRACE_SEQ_BUF_USED(s);
int ret;
- ret = seq_write(m, s->buffer, len);
+ __trace_seq_init(s);
+
+ ret = seq_buf_print_seq(m, &s->seq);
/*
* Only reset this buffer if we successfully wrote to the
@@ -72,24 +82,24 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
*/
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
va_list ap;
- int ret;
- if (s->full || !len)
+ if (s->full)
return;
+ __trace_seq_init(s);
+
va_start(ap, fmt);
- ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+ seq_buf_vprintf(&s->seq, fmt, ap);
va_end(ap);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -104,14 +114,19 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
- s->len += ret;
+ __trace_seq_init(s);
+
+ seq_buf_bitmask(&s->seq, maskp, nmaskbits);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ }
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);
@@ -128,21 +143,22 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
*/
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
int ret;
- if (s->full || !len)
+ if (s->full)
return;
- ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+ __trace_seq_init(s);
+
+ ret = seq_buf_vprintf(&s->seq, fmt, args);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);
@@ -163,21 +179,22 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*/
void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
int ret;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ __trace_seq_init(s);
+
+ ret = seq_buf_bprintf(&s->seq, fmt, binary);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);
@@ -198,13 +215,14 @@ void trace_seq_puts(struct trace_seq *s, const char *str)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, str, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, str, len);
}
EXPORT_SYMBOL_GPL(trace_seq_puts);
@@ -223,12 +241,14 @@ void trace_seq_putc(struct trace_seq *s, unsigned char c)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return;
}
- s->buffer[s->len++] = c;
+ seq_buf_putc(&s->seq, c);
}
EXPORT_SYMBOL_GPL(trace_seq_putc);
@@ -247,19 +267,17 @@ void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, mem, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, mem, len);
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);
-#define MAX_MEMHEX_BYTES 8U
-#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
-
/**
* trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
* @s: trace sequence descriptor
@@ -273,30 +291,26 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- unsigned char hex[HEX_CHARS];
- const unsigned char *data = mem;
- unsigned int start_len;
- int i, j;
+ unsigned int save_len = s->seq.len;
if (s->full)
return;
- while (len) {
- start_len = min(len, HEX_CHARS - 1);
-#ifdef __BIG_ENDIAN
- for (i = 0, j = 0; i < start_len; i++) {
-#else
- for (i = start_len-1, j = 0; i >= 0; i--) {
-#endif
- hex[j++] = hex_asc_hi(data[i]);
- hex[j++] = hex_asc_lo(data[i]);
- }
- if (WARN_ON_ONCE(j == 0 || j/2 > len))
- break;
-
- /* j increments twice per loop */
- len -= j / 2;
- hex[j++] = ' ';
+ __trace_seq_init(s);
+
+ /* Each byte is represented by two chars */
+ if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
+ s->full = 1;
+ return;
+ }
+
+ /* The added spaces can still cause an overflow */
+ seq_buf_putmem_hex(&s->seq, mem, len);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return;
}
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
@@ -315,30 +329,28 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
*/
int trace_seq_path(struct trace_seq *s, const struct path *path)
{
- unsigned char *p;
+ unsigned int save_len = s->seq.len;
+ int ret;
if (s->full)
return 0;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return 0;
}
- p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 1;
- }
- } else {
- s->buffer[s->len++] = '?';
- return 1;
+ ret = seq_buf_path(&s->seq, path);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
}
- s->full = 1;
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_path);
@@ -364,25 +376,7 @@ EXPORT_SYMBOL_GPL(trace_seq_path);
*/
int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
{
- int len;
- int ret;
-
- if (!cnt)
- return 0;
-
- if (s->len <= s->readpos)
- return -EBUSY;
-
- len = s->len - s->readpos;
- if (cnt > len)
- cnt = len;
- ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
- if (ret == cnt)
- return -EFAULT;
-
- cnt -= ret;
-
- s->readpos += cnt;
- return cnt;
+ __trace_seq_init(s);
+ return seq_buf_to_user(&s->seq, ubuf, cnt);
}
EXPORT_SYMBOL_GPL(trace_seq_to_user);
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq
2014-11-14 1:12 ` [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq Steven Rostedt
@ 2014-11-14 16:26 ` Petr Mladek
2014-11-14 17:19 ` Steven Rostedt
2014-11-14 17:23 ` Steven Rostedt
0 siblings, 2 replies; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 16:26 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:12:57, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Create a seq_buf layer that trace_seq sits on. The seq_buf will not
> be limited to page size. This will allow other usages of seq_buf
> instead of a hard set PAGE_SIZE one that trace_seq has.
>
> Link: http://lkml.kernel.org/r/20141104160221.864997179@goodmis.org
>
> Tested-by: Jiri Kosina <jkosina@suse.cz>
> Acked-by: Jiri Kosina <jkosina@suse.cz>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> include/linux/seq_buf.h | 81 +++++++++
> include/linux/trace_seq.h | 12 +-
> kernel/trace/Makefile | 1 +
> kernel/trace/seq_buf.c | 341 +++++++++++++++++++++++++++++++++++
> kernel/trace/trace.c | 39 ++--
> kernel/trace/trace_events.c | 6 +-
> kernel/trace/trace_functions_graph.c | 6 +-
> kernel/trace/trace_seq.c | 172 +++++++++---------
> 8 files changed, 538 insertions(+), 120 deletions(-)
> create mode 100644 include/linux/seq_buf.h
> create mode 100644 kernel/trace/seq_buf.c
>
> diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> new file mode 100644
> index 000000000000..e9a7861595d2
> --- /dev/null
> +++ b/kernel/trace/seq_buf.c
[...]
> +/**
> + * seq_buf_to_user - copy the squence buffer to user space
> + * @s: seq_buf descriptor
> + * @ubuf: The userspace memory location to copy to
> + * @cnt: The amount to copy
> + *
> + * Copies the sequence buffer into the userspace memory pointed to
> + * by @ubuf. It starts from the last read position (@s->readpos)
> + * and writes up to @cnt characters or till it reaches the end of
> + * the content in the buffer (@s->len), which ever comes first.
> + *
> + * On success, it returns a positive number of the number of bytes
> + * it copied.
> + *
> + * On failure it returns -EBUSY if all of the content in the
> + * sequence has been already read, which includes nothing in the
> + * sequence (@s->len == @s->readpos).
> + *
> + * Returns -EFAULT if the copy to userspace fails.
> + */
> +int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
> +{
> + int len;
> + int ret;
> +
> + if (!cnt)
> + return 0;
> +
> + if (s->len <= s->readpos)
> + return -EBUSY;
Ah, we should add here:
if (seq_buf_has_overflowed(s))
return -EINVAL;
It will be especially important after appyling "[RFC][PATCH 17/23 v4]
tracing: Have seq_buf use full buffer".
The patch will make "seq.len = seq.size + 1" when there is an
overflow. It could cause overflow in the following copy_to_user().
It is pity that I have not realized this in the earlier review.
Ach, it was OK in this patch.
> + len = s->len - s->readpos;
> + if (cnt > len)
> + cnt = len;
> + ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
> + if (ret == cnt)
> + return -EFAULT;
> +
> + cnt -= ret;
> +
> + s->readpos += cnt;
> + return cnt;
> +}
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index f5a435a6e8fb..dd43a0d3843a 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -938,19 +938,20 @@ out:
> return ret;
> }
>
> +/* TODO add a seq_buf_to_buffer() */
> static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
> {
> int len;
>
> - if (s->len <= s->readpos)
> + if (s->seq.len <= s->seq.readpos)
> return -EBUSY;
>
> - len = s->len - s->readpos;
> + len = s->seq.len - s->seq.readpos;
Similar problem is here. if (seq.len = seq.size + 1) the
following memcpy might access outside of the buffer.
I am afraid that we need to get rid of all direct uses
of seq.len outside of the seq_buf implemetation.
> if (cnt > len)
> cnt = len;
> - memcpy(buf, s->buffer + s->readpos, cnt);
> + memcpy(buf, s->buffer + s->seq.readpos, cnt);
>
> - s->readpos += cnt;
> + s->seq.readpos += cnt;
> return cnt;
> }
>
> @@ -4314,6 +4315,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
> goto out;
> }
>
> + trace_seq_init(&iter->seq);
> +
> /*
> * We make a copy of the current tracer to avoid concurrent
> * changes on it while we are reading.
> @@ -4510,18 +4513,18 @@ waitagain:
> trace_access_lock(iter->cpu_file);
> while (trace_find_next_entry_inc(iter) != NULL) {
> enum print_line_t ret;
> - int len = iter->seq.len;
> + int len = iter->seq.seq.len;
>
> ret = print_trace_line(iter);
> if (ret == TRACE_TYPE_PARTIAL_LINE) {
> /* don't print partial lines */
> - iter->seq.len = len;
> + iter->seq.seq.len = len;
It is fine here because it just restore the original value but...
> break;
> }
> if (ret != TRACE_TYPE_NO_CONSUME)
> trace_consume(iter);
>
> - if (iter->seq.len >= cnt)
> + if (iter->seq.seq.len >= cnt)
> break;
>
> /*
> @@ -4537,7 +4540,7 @@ waitagain:
>
> /* Now copy what we have to the user */
> sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
> - if (iter->seq.readpos >= iter->seq.len)
> + if (iter->seq.seq.readpos >= iter->seq.seq.len)
> trace_seq_init(&iter->seq);
>
> /*
> @@ -4575,16 +4578,16 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
>
> /* Seq buffer is page-sized, exactly what we need. */
> for (;;) {
> - count = iter->seq.len;
> + count = iter->seq.seq.len;
> ret = print_trace_line(iter);
> - count = iter->seq.len - count;
> + count = iter->seq.seq.len - count;
this looks safe as well;
> if (rem < count) {
> rem = 0;
> - iter->seq.len -= count;
> + iter->seq.seq.len -= count;
> break;
> }
> if (ret == TRACE_TYPE_PARTIAL_LINE) {
> - iter->seq.len -= count;
> + iter->seq.seq.len -= count;
> break;
> }
>
> @@ -4665,13 +4668,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
> /* Copy the data into the page, so we can start over. */
> ret = trace_seq_to_buffer(&iter->seq,
> page_address(spd.pages[i]),
> - iter->seq.len);
> + iter->seq.seq.len);
> if (ret < 0) {
> __free_page(spd.pages[i]);
> break;
> }
> spd.partial[i].offset = 0;
> - spd.partial[i].len = iter->seq.len;
> + spd.partial[i].len = iter->seq.seq.len;
>
> trace_seq_init(&iter->seq);
> }
> @@ -5672,7 +5675,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
> cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
> trace_seq_printf(s, "read events: %ld\n", cnt);
>
> - count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
> + count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);
but this looks dangerous.
> kfree(s);
>
> @@ -6635,11 +6638,11 @@ void
> trace_printk_seq(struct trace_seq *s)
> {
> /* Probably should print a warning here. */
> - if (s->len >= TRACE_MAX_PRINT)
> - s->len = TRACE_MAX_PRINT;
> + if (s->seq.len >= TRACE_MAX_PRINT)
> + s->seq.len = TRACE_MAX_PRINT;
looks safe
> /* should be zero ended, but we are paranoid. */
> - s->buffer[s->len] = 0;
> + s->buffer[s->seq.len] = 0;
>
> printk(KERN_TRACE "%s", s->buffer);
>
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 0cc51edde3a8..33525bf6cbf5 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1044,7 +1044,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
> mutex_unlock(&event_mutex);
>
> if (file)
> - r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
> + r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
dangerous...
[...]
> diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
> index e54c0a1fb3f0..3c63b619d6b7 100644
> --- a/kernel/trace/trace_seq.c
> +++ b/kernel/trace/trace_seq.c
[...]
> @@ -72,24 +82,24 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
> */
> void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
> {
> - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> + unsigned int save_len = s->seq.len;
> va_list ap;
> - int ret;
>
> - if (s->full || !len)
> + if (s->full)
> return;
>
> + __trace_seq_init(s);
> +
> va_start(ap, fmt);
> - ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
> + seq_buf_vprintf(&s->seq, fmt, ap);
> va_end(ap);
>
> /* If we can't write it all, don't bother writing anything */
> - if (ret >= len) {
> + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> + s->seq.len = save_len;
> s->full = 1;
> return;
The return is redundant here.
> }
> -
> - s->len += ret;
> }
> EXPORT_SYMBOL_GPL(trace_seq_printf);
>
> @@ -104,14 +114,19 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
> void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
> int nmaskbits)
> {
> - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> - int ret;
> + unsigned int save_len = s->seq.len;
>
> - if (s->full || !len)
> + if (s->full)
> return;
>
> - ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
> - s->len += ret;
> + __trace_seq_init(s);
> +
> + seq_buf_bitmask(&s->seq, maskp, nmaskbits);
> +
> + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> + s->seq.len = save_len;
> + s->full = 1;
> + }
> }
> EXPORT_SYMBOL_GPL(trace_seq_bitmask);
>
> @@ -128,21 +143,22 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
> */
> void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
> {
> - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> + unsigned int save_len = s->seq.len;
> int ret;
>
> - if (s->full || !len)
> + if (s->full)
> return;
>
> - ret = vsnprintf(s->buffer + s->len, len, fmt, args);
> + __trace_seq_init(s);
> +
> + ret = seq_buf_vprintf(&s->seq, fmt, args);
The ret value is not used.
> /* If we can't write it all, don't bother writing anything */
> - if (ret >= len) {
> + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> + s->seq.len = save_len;
> s->full = 1;
> return;
The return is redundant.
The above mentioned potential overflows happen only if
we apply "[RFC][PATCH 17/23 v4]
tracing: Have seq_buf use full buffer". The code is safe
at this stage. The other problems are minor.
If you decide to address the potential overflows in another
patch, feel free to add to this one:
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Best Regards,
Petr
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq
2014-11-14 16:26 ` Petr Mladek
@ 2014-11-14 17:19 ` Steven Rostedt
2014-11-14 17:23 ` Steven Rostedt
1 sibling, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:19 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 17:26:52 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> On Thu 2014-11-13 20:12:57, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > Create a seq_buf layer that trace_seq sits on. The seq_buf will not
> > be limited to page size. This will allow other usages of seq_buf
> > instead of a hard set PAGE_SIZE one that trace_seq has.
> >
> > Link: http://lkml.kernel.org/r/20141104160221.864997179@goodmis.org
> >
> > Tested-by: Jiri Kosina <jkosina@suse.cz>
> > Acked-by: Jiri Kosina <jkosina@suse.cz>
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > include/linux/seq_buf.h | 81 +++++++++
> > include/linux/trace_seq.h | 12 +-
> > kernel/trace/Makefile | 1 +
> > kernel/trace/seq_buf.c | 341 +++++++++++++++++++++++++++++++++++
> > kernel/trace/trace.c | 39 ++--
> > kernel/trace/trace_events.c | 6 +-
> > kernel/trace/trace_functions_graph.c | 6 +-
> > kernel/trace/trace_seq.c | 172 +++++++++---------
> > 8 files changed, 538 insertions(+), 120 deletions(-)
> > create mode 100644 include/linux/seq_buf.h
> > create mode 100644 kernel/trace/seq_buf.c
> >
> > diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> > new file mode 100644
> > index 000000000000..e9a7861595d2
> > --- /dev/null
> > +++ b/kernel/trace/seq_buf.c
> [...]
> > +/**
> > + * seq_buf_to_user - copy the squence buffer to user space
> > + * @s: seq_buf descriptor
> > + * @ubuf: The userspace memory location to copy to
> > + * @cnt: The amount to copy
> > + *
> > + * Copies the sequence buffer into the userspace memory pointed to
> > + * by @ubuf. It starts from the last read position (@s->readpos)
> > + * and writes up to @cnt characters or till it reaches the end of
> > + * the content in the buffer (@s->len), which ever comes first.
> > + *
> > + * On success, it returns a positive number of the number of bytes
> > + * it copied.
> > + *
> > + * On failure it returns -EBUSY if all of the content in the
> > + * sequence has been already read, which includes nothing in the
> > + * sequence (@s->len == @s->readpos).
> > + *
> > + * Returns -EFAULT if the copy to userspace fails.
> > + */
> > +int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
> > +{
> > + int len;
> > + int ret;
> > +
> > + if (!cnt)
> > + return 0;
> > +
> > + if (s->len <= s->readpos)
> > + return -EBUSY;
>
> Ah, we should add here:
>
> if (seq_buf_has_overflowed(s))
> return -EINVAL;
>
> It will be especially important after appyling "[RFC][PATCH 17/23 v4]
> tracing: Have seq_buf use full buffer".
>
> The patch will make "seq.len = seq.size + 1" when there is an
> overflow. It could cause overflow in the following copy_to_user().
>
> It is pity that I have not realized this in the earlier review.
> Ach, it was OK in this patch.
Actually, I wouldn't use -EINVAL but instead use the seq_buf_used()
helper function:
len = seq_buf_used(s);
>
> > + len = s->len - s->readpos;
> > + if (cnt > len)
> > + cnt = len;
> > + ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
> > + if (ret == cnt)
> > + return -EFAULT;
> > +
> > + cnt -= ret;
> > +
> > + s->readpos += cnt;
> > + return cnt;
> > +}
> > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> > index f5a435a6e8fb..dd43a0d3843a 100644
> > --- a/kernel/trace/trace.c
> > +++ b/kernel/trace/trace.c
> > @@ -938,19 +938,20 @@ out:
> > return ret;
> > }
> >
> > +/* TODO add a seq_buf_to_buffer() */
> > static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
> > {
> > int len;
> >
> > - if (s->len <= s->readpos)
> > + if (s->seq.len <= s->seq.readpos)
> > return -EBUSY;
> >
> > - len = s->len - s->readpos;
> > + len = s->seq.len - s->seq.readpos;
>
> Similar problem is here. if (seq.len = seq.size + 1) the
> following memcpy might access outside of the buffer.
>
> I am afraid that we need to get rid of all direct uses
> of seq.len outside of the seq_buf implemetation.
Yep, I agree. The seq_buf_used() should be used instead.
>
> > if (cnt > len)
> > cnt = len;
> > - memcpy(buf, s->buffer + s->readpos, cnt);
> > + memcpy(buf, s->buffer + s->seq.readpos, cnt);
> >
> > - s->readpos += cnt;
> > + s->seq.readpos += cnt;
> > return cnt;
> > }
> >
> > @@ -4314,6 +4315,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
> > goto out;
> > }
> >
> > + trace_seq_init(&iter->seq);
> > +
> > /*
> > * We make a copy of the current tracer to avoid concurrent
> > * changes on it while we are reading.
> > @@ -4510,18 +4513,18 @@ waitagain:
> > trace_access_lock(iter->cpu_file);
> > while (trace_find_next_entry_inc(iter) != NULL) {
> > enum print_line_t ret;
> > - int len = iter->seq.len;
> > + int len = iter->seq.seq.len;
> >
> > ret = print_trace_line(iter);
> > if (ret == TRACE_TYPE_PARTIAL_LINE) {
> > /* don't print partial lines */
> > - iter->seq.len = len;
> > + iter->seq.seq.len = len;
>
> It is fine here because it just restore the original value but...
but?
>
> > break;
> > }
> > if (ret != TRACE_TYPE_NO_CONSUME)
> > trace_consume(iter);
> >
> > - if (iter->seq.len >= cnt)
> > + if (iter->seq.seq.len >= cnt)
> > break;
> >
> > /*
> > @@ -4537,7 +4540,7 @@ waitagain:
> >
> > /* Now copy what we have to the user */
> > sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
> > - if (iter->seq.readpos >= iter->seq.len)
> > + if (iter->seq.seq.readpos >= iter->seq.seq.len)
> > trace_seq_init(&iter->seq);
> >
> > /*
> > @@ -4575,16 +4578,16 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
> >
> > /* Seq buffer is page-sized, exactly what we need. */
> > for (;;) {
> > - count = iter->seq.len;
> > + count = iter->seq.seq.len;
> > ret = print_trace_line(iter);
> > - count = iter->seq.len - count;
> > + count = iter->seq.seq.len - count;
>
> this looks safe as well;
This should use the seq_buf_used() as well.
>
> > if (rem < count) {
> > rem = 0;
> > - iter->seq.len -= count;
> > + iter->seq.seq.len -= count;
> > break;
> > }
> > if (ret == TRACE_TYPE_PARTIAL_LINE) {
> > - iter->seq.len -= count;
> > + iter->seq.seq.len -= count;
> > break;
> > }
> >
> > @@ -4665,13 +4668,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
> > /* Copy the data into the page, so we can start over. */
> > ret = trace_seq_to_buffer(&iter->seq,
> > page_address(spd.pages[i]),
> > - iter->seq.len);
> > + iter->seq.seq.len);
> > if (ret < 0) {
> > __free_page(spd.pages[i]);
> > break;
> > }
> > spd.partial[i].offset = 0;
> > - spd.partial[i].len = iter->seq.len;
> > + spd.partial[i].len = iter->seq.seq.len;
> >
> > trace_seq_init(&iter->seq);
> > }
> > @@ -5672,7 +5675,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
> > cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
> > trace_seq_printf(s, "read events: %ld\n", cnt);
> >
> > - count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
> > + count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);
>
> but this looks dangerous.
Agreed.
>
> > kfree(s);
> >
> > @@ -6635,11 +6638,11 @@ void
> > trace_printk_seq(struct trace_seq *s)
> > {
> > /* Probably should print a warning here. */
> > - if (s->len >= TRACE_MAX_PRINT)
> > - s->len = TRACE_MAX_PRINT;
> > + if (s->seq.len >= TRACE_MAX_PRINT)
> > + s->seq.len = TRACE_MAX_PRINT;
>
> looks safe
Yeah.
>
>
> > /* should be zero ended, but we are paranoid. */
> > - s->buffer[s->len] = 0;
> > + s->buffer[s->seq.len] = 0;
> >
> > printk(KERN_TRACE "%s", s->buffer);
> >
> > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> > index 0cc51edde3a8..33525bf6cbf5 100644
> > --- a/kernel/trace/trace_events.c
> > +++ b/kernel/trace/trace_events.c
> > @@ -1044,7 +1044,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
> > mutex_unlock(&event_mutex);
> >
> > if (file)
> > - r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
> > + r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
>
> dangerous...
Agreed.
>
> [...]
>
> > diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
> > index e54c0a1fb3f0..3c63b619d6b7 100644
> > --- a/kernel/trace/trace_seq.c
> > +++ b/kernel/trace/trace_seq.c
> [...]
> > @@ -72,24 +82,24 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
> > */
> > void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
> > {
> > - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> > + unsigned int save_len = s->seq.len;
> > va_list ap;
> > - int ret;
> >
> > - if (s->full || !len)
> > + if (s->full)
> > return;
> >
> > + __trace_seq_init(s);
> > +
> > va_start(ap, fmt);
> > - ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
> > + seq_buf_vprintf(&s->seq, fmt, ap);
> > va_end(ap);
> >
> > /* If we can't write it all, don't bother writing anything */
> > - if (ret >= len) {
> > + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> > + s->seq.len = save_len;
> > s->full = 1;
> > return;
>
> The return is redundant here.
Heh, yep. Doing a lot of rather trivial updates makes one do stupid
things like this.
>
> > }
> > -
> > - s->len += ret;
> > }
> > EXPORT_SYMBOL_GPL(trace_seq_printf);
> >
> > @@ -104,14 +114,19 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
> > void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
> > int nmaskbits)
> > {
> > - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> > - int ret;
> > + unsigned int save_len = s->seq.len;
> >
> > - if (s->full || !len)
> > + if (s->full)
> > return;
> >
> > - ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
> > - s->len += ret;
> > + __trace_seq_init(s);
> > +
> > + seq_buf_bitmask(&s->seq, maskp, nmaskbits);
> > +
> > + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> > + s->seq.len = save_len;
> > + s->full = 1;
> > + }
> > }
> > EXPORT_SYMBOL_GPL(trace_seq_bitmask);
> >
> > @@ -128,21 +143,22 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
> > */
> > void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
> > {
> > - unsigned int len = TRACE_SEQ_BUF_LEFT(s);
> > + unsigned int save_len = s->seq.len;
> > int ret;
> >
> > - if (s->full || !len)
> > + if (s->full)
> > return;
> >
> > - ret = vsnprintf(s->buffer + s->len, len, fmt, args);
> > + __trace_seq_init(s);
> > +
> > + ret = seq_buf_vprintf(&s->seq, fmt, args);
>
> The ret value is not used.
Yep, I'll nuke it.
>
> > /* If we can't write it all, don't bother writing anything */
> > - if (ret >= len) {
> > + if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> > + s->seq.len = save_len;
> > s->full = 1;
> > return;
>
> The return is redundant.
Yep, Just missed it.
>
> The above mentioned potential overflows happen only if
> we apply "[RFC][PATCH 17/23 v4]
> tracing: Have seq_buf use full buffer". The code is safe
> at this stage. The other problems are minor.
>
> If you decide to address the potential overflows in another
> patch, feel free to add to this one:
Yeah, I'll do that after the seq_buf_used() is introduced.
>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
Thanks!
-- Steve
>
> Best Regards,
> Petr
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq
2014-11-14 16:26 ` Petr Mladek
2014-11-14 17:19 ` Steven Rostedt
@ 2014-11-14 17:23 ` Steven Rostedt
1 sibling, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:23 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 17:26:52 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> The return is redundant.
>
> The above mentioned potential overflows happen only if
> we apply "[RFC][PATCH 17/23 v4]
> tracing: Have seq_buf use full buffer". The code is safe
> at this stage. The other problems are minor.
>
> If you decide to address the potential overflows in another
> patch, feel free to add to this one:
>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
Thanks.
I removed the redundant returns and the unused ret variable. I left the
dangerous copies in as I plan on addressing that after I introduce
seq_buf_used().
-- Steve
Here's the new patch:
>From 17dc0a77777556c998849dabe27d367a5702a967 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 25 Jun 2014 15:54:42 -0400
Subject: [PATCH] tracing: Create seq_buf layer in trace_seq
Create a seq_buf layer that trace_seq sits on. The seq_buf will not
be limited to page size. This will allow other usages of seq_buf
instead of a hard set PAGE_SIZE one that trace_seq has.
Link: http://lkml.kernel.org/r/20141104160221.864997179@goodmis.org
Link: http://lkml.kernel.org/r/20141114011412.170377300@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 81 +++++++++
include/linux/trace_seq.h | 12 +-
kernel/trace/Makefile | 1 +
kernel/trace/seq_buf.c | 341 +++++++++++++++++++++++++++++++++++
kernel/trace/trace.c | 39 ++--
kernel/trace/trace_events.c | 6 +-
kernel/trace/trace_functions_graph.c | 6 +-
kernel/trace/trace_seq.c | 177 +++++++++---------
8 files changed, 538 insertions(+), 125 deletions(-)
create mode 100644 include/linux/seq_buf.h
create mode 100644 kernel/trace/seq_buf.c
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
new file mode 100644
index 000000000000..4f7a96a9d71a
--- /dev/null
+++ b/include/linux/seq_buf.h
@@ -0,0 +1,81 @@
+#ifndef _LINUX_SEQ_BUF_H
+#define _LINUX_SEQ_BUF_H
+
+#include <linux/fs.h>
+
+/*
+ * Trace sequences are used to allow a function to call several other functions
+ * to create a string of data to use.
+ */
+
+/**
+ * seq_buf - seq buffer structure
+ * @buffer: pointer to the buffer
+ * @size: size of the buffer
+ * @len: the amount of data inside the buffer
+ * @readpos: The next position to read in the buffer.
+ */
+struct seq_buf {
+ unsigned char *buffer;
+ unsigned int size;
+ unsigned int len;
+ unsigned int readpos;
+};
+
+static inline void
+seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
+{
+ s->buffer = buf;
+ s->size = size;
+ s->len = 0;
+ s->readpos = 0;
+}
+
+/*
+ * seq_buf have a buffer that might overflow. When this happens
+ * the len and size are set to be equal.
+ */
+static inline bool
+seq_buf_has_overflowed(struct seq_buf *s)
+{
+ return s->len == s->size;
+}
+
+static inline void
+seq_buf_set_overflow(struct seq_buf *s)
+{
+ s->len = s->size;
+}
+
+/*
+ * How much buffer is left on the seq_buf?
+ */
+static inline unsigned int
+seq_buf_buffer_left(struct seq_buf *s)
+{
+ if (seq_buf_has_overflowed(s))
+ return 0;
+
+ return (s->size - 1) - s->len;
+}
+
+extern __printf(2, 3)
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
+extern __printf(2, 0)
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
+extern int
+seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
+extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
+extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
+ int cnt);
+extern int seq_buf_puts(struct seq_buf *s, const char *str);
+extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
+extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
+extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len);
+extern int seq_buf_path(struct seq_buf *s, const struct path *path);
+
+extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits);
+
+#endif /* _LINUX_SEQ_BUF_H */
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index db8a73224f1a..85d37106be3d 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H
-#include <linux/fs.h>
+#include <linux/seq_buf.h>
#include <asm/page.h>
@@ -12,16 +12,14 @@
struct trace_seq {
unsigned char buffer[PAGE_SIZE];
- unsigned int len;
- unsigned int readpos;
+ struct seq_buf seq;
int full;
};
static inline void
trace_seq_init(struct trace_seq *s)
{
- s->len = 0;
- s->readpos = 0;
+ seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
s->full = 0;
}
@@ -37,7 +35,7 @@ trace_seq_init(struct trace_seq *s)
static inline unsigned char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
- return s->buffer + s->len;
+ return s->buffer + s->seq.len;
}
/**
@@ -49,7 +47,7 @@ trace_seq_buffer_ptr(struct trace_seq *s)
*/
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
- return s->full || s->len > PAGE_SIZE - 1;
+ return s->full || seq_buf_has_overflowed(&s->seq);
}
/*
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 67d6369ddf83..edc98c72a634 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
+obj-$(CONFIG_TRACING) += seq_buf.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
new file mode 100644
index 000000000000..e9a7861595d2
--- /dev/null
+++ b/kernel/trace/seq_buf.c
@@ -0,0 +1,341 @@
+/*
+ * seq_buf.c
+ *
+ * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The seq_buf is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the seq_buf must be initialized with seq_buf_init().
+ * This will set up the counters within the descriptor. You can call
+ * seq_buf_init() more than once to reset the seq_buf to start
+ * from scratch.
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/seq_buf.h>
+
+/* How much buffer is written? */
+#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
+
+/**
+ * seq_buf_print_seq - move the contents of seq_buf into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the seq_buf descriptor that is the source.
+ *
+ * Returns zero on success, non zero otherwise
+ */
+int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
+{
+ unsigned int len = SEQ_BUF_USED(s);
+
+ return seq_write(m, s->buffer, len);
+}
+
+/**
+ * seq_buf_vprintf - sequence printing of information.
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ * @args: va_list of arguments from a printf() type function
+ *
+ * Writes a vnprintf() format into the sequencce buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
+{
+ int len;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
+ if (s->len + len < s->size) {
+ s->len += len;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_printf - sequence printing of information
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ *
+ * Writes a printf() format into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = seq_buf_vprintf(s, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
+/**
+ * seq_buf_bitmask - write a bitmask array in its ASCII representation
+ * @s: seq_buf descriptor
+ * @maskp: points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits: The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ /*
+ * The last byte of the buffer is used to determine if we
+ * overflowed or not.
+ */
+ if (len > 1) {
+ ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
+ if (ret < len) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_bprintf - Write the printf string from binary arguments
+ * @s: seq_buf descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ if (s->len + ret < s->size) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_puts - sequence printing of simple string
+ * @s: seq_buf descriptor
+ * @str: simple string to record
+ *
+ * Copy a simple string into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_puts(struct seq_buf *s, const char *str)
+{
+ unsigned int len = strlen(str);
+
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, str, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putc - sequence printing of simple character
+ * @s: seq_buf descriptor
+ * @c: simple character to record
+ *
+ * Copy a single character into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putc(struct seq_buf *s, unsigned char c)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + 1 < s->size) {
+ s->buffer[s->len++] = c;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putmem - write raw data into the sequenc buffer
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, mem, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+#define MAX_MEMHEX_BYTES 8U
+#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
+
+/**
+ * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to seq_buf_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len)
+{
+ unsigned char hex[HEX_CHARS];
+ const unsigned char *data = mem;
+ unsigned int start_len;
+ int i, j;
+
+ WARN_ON(s->size == 0);
+
+ while (len) {
+ start_len = min(len, HEX_CHARS - 1);
+#ifdef __BIG_ENDIAN
+ for (i = 0, j = 0; i < start_len; i++) {
+#else
+ for (i = start_len-1, j = 0; i >= 0; i--) {
+#endif
+ hex[j++] = hex_asc_hi(data[i]);
+ hex[j++] = hex_asc_lo(data[i]);
+ }
+ if (WARN_ON_ONCE(j == 0 || j/2 > len))
+ break;
+
+ /* j increments twice per loop */
+ len -= j / 2;
+ hex[j++] = ' ';
+
+ seq_buf_putmem(s, hex, j);
+ if (seq_buf_has_overflowed(s))
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * seq_buf_path - copy a path into the sequence buffer
+ * @s: seq_buf descriptor
+ * @path: path to write into the sequence buffer.
+ *
+ * Write a path name into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_path(struct seq_buf *s, const struct path *path)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ unsigned char *p;
+
+ WARN_ON(s->size == 0);
+
+ p = d_path(path, s->buffer + s->len, len);
+ if (!IS_ERR(p)) {
+ p = mangle_path(s->buffer + s->len, p, "\n");
+ if (p) {
+ s->len = p - s->buffer;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_to_user - copy the squence buffer to user space
+ * @s: seq_buf descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequence (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
+{
+ int len;
+ int ret;
+
+ if (!cnt)
+ return 0;
+
+ if (s->len <= s->readpos)
+ return -EBUSY;
+
+ len = s->len - s->readpos;
+ if (cnt > len)
+ cnt = len;
+ ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+ if (ret == cnt)
+ return -EFAULT;
+
+ cnt -= ret;
+
+ s->readpos += cnt;
+ return cnt;
+}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3ce3c4ccfc94..7d7a07e9b9e9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -939,19 +939,20 @@ out:
return ret;
}
+/* TODO add a seq_buf_to_buffer() */
static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
- if (s->len <= s->readpos)
+ if (s->seq.len <= s->seq.readpos)
return -EBUSY;
- len = s->len - s->readpos;
+ len = s->seq.len - s->seq.readpos;
if (cnt > len)
cnt = len;
- memcpy(buf, s->buffer + s->readpos, cnt);
+ memcpy(buf, s->buffer + s->seq.readpos, cnt);
- s->readpos += cnt;
+ s->seq.readpos += cnt;
return cnt;
}
@@ -4315,6 +4316,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
goto out;
}
+ trace_seq_init(&iter->seq);
+
/*
* We make a copy of the current tracer to avoid concurrent
* changes on it while we are reading.
@@ -4511,18 +4514,18 @@ waitagain:
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
- int len = iter->seq.len;
+ int len = iter->seq.seq.len;
ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
- iter->seq.len = len;
+ iter->seq.seq.len = len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
- if (iter->seq.len >= cnt)
+ if (iter->seq.seq.len >= cnt)
break;
/*
@@ -4538,7 +4541,7 @@ waitagain:
/* Now copy what we have to the user */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
- if (iter->seq.readpos >= iter->seq.len)
+ if (iter->seq.seq.readpos >= iter->seq.seq.len)
trace_seq_init(&iter->seq);
/*
@@ -4576,16 +4579,16 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
- count = iter->seq.len;
+ count = iter->seq.seq.len;
ret = print_trace_line(iter);
- count = iter->seq.len - count;
+ count = iter->seq.seq.len - count;
if (rem < count) {
rem = 0;
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}
@@ -4666,13 +4669,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
/* Copy the data into the page, so we can start over. */
ret = trace_seq_to_buffer(&iter->seq,
page_address(spd.pages[i]),
- iter->seq.len);
+ iter->seq.seq.len);
if (ret < 0) {
__free_page(spd.pages[i]);
break;
}
spd.partial[i].offset = 0;
- spd.partial[i].len = iter->seq.len;
+ spd.partial[i].len = iter->seq.seq.len;
trace_seq_init(&iter->seq);
}
@@ -5673,7 +5676,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "read events: %ld\n", cnt);
- count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
+ count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -6636,11 +6639,11 @@ void
trace_printk_seq(struct trace_seq *s)
{
/* Probably should print a warning here. */
- if (s->len >= TRACE_MAX_PRINT)
- s->len = TRACE_MAX_PRINT;
+ if (s->seq.len >= TRACE_MAX_PRINT)
+ s->seq.len = TRACE_MAX_PRINT;
/* should be zero ended, but we are paranoid. */
- s->buffer[s->len] = 0;
+ s->buffer[s->seq.len] = 0;
printk(KERN_TRACE "%s", s->buffer);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f9d0cbe014b7..4d0067dd7f88 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1044,7 +1044,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
mutex_unlock(&event_mutex);
if (file)
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -1210,7 +1210,7 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);
print_subsystem_event_filter(system, s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
@@ -1265,7 +1265,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
trace_seq_init(s);
func(s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
kfree(s);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 100288d10e1f..6d1342ae7a44 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1154,9 +1154,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
}
/* Strip ending newline */
- if (s->buffer[s->len - 1] == '\n') {
- s->buffer[s->len - 1] = '\0';
- s->len--;
+ if (s->buffer[s->seq.len - 1] == '\n') {
+ s->buffer[s->seq.len - 1] = '\0';
+ s->seq.len--;
}
trace_seq_puts(s, " */\n");
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index fabfa0f190a3..b623b7295864 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -27,10 +27,19 @@
#include <linux/trace_seq.h>
/* How much buffer is left on the trace_seq? */
-#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len)
+#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1))
+#define TRACE_SEQ_BUF_USED(s) min((s)->seq.len, (unsigned int)(PAGE_SIZE - 1))
+
+/*
+ * trace_seq should work with being initialized with 0s.
+ */
+static inline void __trace_seq_init(struct trace_seq *s)
+{
+ if (unlikely(!s->seq.size))
+ trace_seq_init(s);
+}
/**
* trace_print_seq - move the contents of trace_seq into a seq_file
@@ -43,10 +52,11 @@
*/
int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
- unsigned int len = TRACE_SEQ_BUF_USED(s);
int ret;
- ret = seq_write(m, s->buffer, len);
+ __trace_seq_init(s);
+
+ ret = seq_buf_print_seq(m, &s->seq);
/*
* Only reset this buffer if we successfully wrote to the
@@ -72,24 +82,23 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
*/
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
va_list ap;
- int ret;
- if (s->full || !len)
+ if (s->full)
return;
+ __trace_seq_init(s);
+
va_start(ap, fmt);
- ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+ seq_buf_vprintf(&s->seq, fmt, ap);
va_end(ap);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
- return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -104,14 +113,19 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
- s->len += ret;
+ __trace_seq_init(s);
+
+ seq_buf_bitmask(&s->seq, maskp, nmaskbits);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ }
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);
@@ -128,21 +142,20 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
*/
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+ __trace_seq_init(s);
+
+ seq_buf_vprintf(&s->seq, fmt, args);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
- return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);
@@ -163,21 +176,22 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*/
void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
int ret;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ __trace_seq_init(s);
+
+ ret = seq_buf_bprintf(&s->seq, fmt, binary);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);
@@ -198,13 +212,14 @@ void trace_seq_puts(struct trace_seq *s, const char *str)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, str, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, str, len);
}
EXPORT_SYMBOL_GPL(trace_seq_puts);
@@ -223,12 +238,14 @@ void trace_seq_putc(struct trace_seq *s, unsigned char c)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return;
}
- s->buffer[s->len++] = c;
+ seq_buf_putc(&s->seq, c);
}
EXPORT_SYMBOL_GPL(trace_seq_putc);
@@ -247,19 +264,17 @@ void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, mem, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, mem, len);
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);
-#define MAX_MEMHEX_BYTES 8U
-#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
-
/**
* trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
* @s: trace sequence descriptor
@@ -273,32 +288,26 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- unsigned char hex[HEX_CHARS];
- const unsigned char *data = mem;
- unsigned int start_len;
- int i, j;
+ unsigned int save_len = s->seq.len;
if (s->full)
return;
- while (len) {
- start_len = min(len, HEX_CHARS - 1);
-#ifdef __BIG_ENDIAN
- for (i = 0, j = 0; i < start_len; i++) {
-#else
- for (i = start_len-1, j = 0; i >= 0; i--) {
-#endif
- hex[j++] = hex_asc_hi(data[i]);
- hex[j++] = hex_asc_lo(data[i]);
- }
- if (WARN_ON_ONCE(j == 0 || j/2 > len))
- break;
-
- /* j increments twice per loop */
- len -= j / 2;
- hex[j++] = ' ';
-
- trace_seq_putmem(s, hex, j);
+ __trace_seq_init(s);
+
+ /* Each byte is represented by two chars */
+ if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
+ s->full = 1;
+ return;
+ }
+
+ /* The added spaces can still cause an overflow */
+ seq_buf_putmem_hex(&s->seq, mem, len);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return;
}
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
@@ -317,30 +326,28 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
*/
int trace_seq_path(struct trace_seq *s, const struct path *path)
{
- unsigned char *p;
+ unsigned int save_len = s->seq.len;
+ int ret;
if (s->full)
return 0;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return 0;
}
- p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 1;
- }
- } else {
- s->buffer[s->len++] = '?';
- return 1;
+ ret = seq_buf_path(&s->seq, path);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
}
- s->full = 1;
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_path);
@@ -366,25 +373,7 @@ EXPORT_SYMBOL_GPL(trace_seq_path);
*/
int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
{
- int len;
- int ret;
-
- if (!cnt)
- return 0;
-
- if (s->len <= s->readpos)
- return -EBUSY;
-
- len = s->len - s->readpos;
- if (cnt > len)
- cnt = len;
- ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
- if (ret == cnt)
- return -EFAULT;
-
- cnt -= ret;
-
- s->readpos += cnt;
- return cnt;
+ __trace_seq_init(s);
+ return seq_buf_to_user(&s->seq, ubuf, cnt);
}
EXPORT_SYMBOL_GPL(trace_seq_to_user);
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path()
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (12 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 16:53 ` Petr Mladek
2014-11-14 1:12 ` [RFC][PATCH 15/23 v4] tracing: Convert seq_buf fields to be like seq_file fields Steven Rostedt
` (8 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0014-tracing-Convert-seq_buf_path-to-be-like-seq_path.patch --]
[-- Type: text/plain, Size: 3367 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Rewrite seq_buf_path() like it is done in seq_path() and allow
it to accept any escape character instead of just "\n".
Making seq_buf_path() like seq_path() will help prevent problems
when converting seq_file to use the seq_buf logic.
Link: http://lkml.kernel.org/r/20141104160222.048795666@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 2 +-
kernel/trace/seq_buf.c | 28 ++++++++++++++++------------
kernel/trace/trace_seq.c | 4 ++--
3 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 4f7a96a9d71a..38770688a627 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -73,7 +73,7 @@ extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
unsigned int len);
-extern int seq_buf_path(struct seq_buf *s, const struct path *path);
+extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
int nmaskbits);
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index e9a7861595d2..7dac34d1235b 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -272,28 +272,32 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
* seq_buf_path - copy a path into the sequence buffer
* @s: seq_buf descriptor
* @path: path to write into the sequence buffer.
+ * @esc: set of characters to escape in the output
*
* Write a path name into the sequence buffer.
*
- * Returns zero on success, -1 on overflow
+ * Returns the number of written bytes on success, -1 on overflow
*/
-int seq_buf_path(struct seq_buf *s, const struct path *path)
+int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
- unsigned int len = seq_buf_buffer_left(s);
- unsigned char *p;
+ char *buf = s->buffer + s->len;
+ size_t size = seq_buf_buffer_left(s);
+ int res = -1;
WARN_ON(s->size == 0);
- p = d_path(path, s->buffer + s->len, len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 0;
+ if (size) {
+ char *p = d_path(path, buf, size);
+ if (!IS_ERR(p)) {
+ char *end = mangle_path(buf, p, esc);
+ if (end)
+ res = end - buf;
}
}
- seq_buf_set_overflow(s);
- return -1;
+ if (res > 0)
+ s->len += res;
+
+ return res;
}
/**
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 3c63b619d6b7..475412e31de5 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -342,7 +342,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
return 0;
}
- ret = seq_buf_path(&s->seq, path);
+ ret = seq_buf_path(&s->seq, path, "\n");
if (unlikely(seq_buf_has_overflowed(&s->seq))) {
s->seq.len = save_len;
@@ -350,7 +350,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
return 0;
}
- return ret;
+ return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_path);
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path()
2014-11-14 1:12 ` [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path() Steven Rostedt
@ 2014-11-14 16:53 ` Petr Mladek
2014-11-14 17:47 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 16:53 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:12:58, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Rewrite seq_buf_path() like it is done in seq_path() and allow
> it to accept any escape character instead of just "\n".
>
> Making seq_buf_path() like seq_path() will help prevent problems
> when converting seq_file to use the seq_buf logic.
>
> Link: http://lkml.kernel.org/r/20141104160222.048795666@goodmis.org
>
> Tested-by: Jiri Kosina <jkosina@suse.cz>
> Acked-by: Jiri Kosina <jkosina@suse.cz>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> include/linux/seq_buf.h | 2 +-
> kernel/trace/seq_buf.c | 28 ++++++++++++++++------------
> kernel/trace/trace_seq.c | 4 ++--
> 3 files changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 4f7a96a9d71a..38770688a627 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -73,7 +73,7 @@ extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
> extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
> extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
> unsigned int len);
> -extern int seq_buf_path(struct seq_buf *s, const struct path *path);
> +extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
>
> extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
> int nmaskbits);
> diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> index e9a7861595d2..7dac34d1235b 100644
> --- a/kernel/trace/seq_buf.c
> +++ b/kernel/trace/seq_buf.c
> @@ -272,28 +272,32 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
> * seq_buf_path - copy a path into the sequence buffer
> * @s: seq_buf descriptor
> * @path: path to write into the sequence buffer.
> + * @esc: set of characters to escape in the output
> *
> * Write a path name into the sequence buffer.
> *
> - * Returns zero on success, -1 on overflow
> + * Returns the number of written bytes on success, -1 on overflow
> */
> -int seq_buf_path(struct seq_buf *s, const struct path *path)
> +int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
> {
> - unsigned int len = seq_buf_buffer_left(s);
> - unsigned char *p;
> + char *buf = s->buffer + s->len;
> + size_t size = seq_buf_buffer_left(s);
> + int res = -1;
>
> WARN_ON(s->size == 0);
>
> - p = d_path(path, s->buffer + s->len, len);
> - if (!IS_ERR(p)) {
> - p = mangle_path(s->buffer + s->len, p, "\n");
> - if (p) {
> - s->len = p - s->buffer;
> - return 0;
> + if (size) {
> + char *p = d_path(path, buf, size);
> + if (!IS_ERR(p)) {
> + char *end = mangle_path(buf, p, esc);
> + if (end)
> + res = end - buf;
> }
> }
> - seq_buf_set_overflow(s);
> - return -1;
> + if (res > 0)
> + s->len += res;
> +
> + return res;
> }
>
> /**
> diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
> index 3c63b619d6b7..475412e31de5 100644
> --- a/kernel/trace/trace_seq.c
> +++ b/kernel/trace/trace_seq.c
> @@ -342,7 +342,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
> return 0;
> }
>
> - ret = seq_buf_path(&s->seq, path);
> + ret = seq_buf_path(&s->seq, path, "\n");
>
> if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> s->seq.len = save_len;
> @@ -350,7 +350,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
> return 0;
> }
>
> - return ret;
> + return 1;
Ah, I have just realized that this should return -1 when
seq_buf_path() returns -1.
Note that set_buf_path() does not longer calls seq_buf_set_overflow(s)
when the path handling fails. Therefore the above check for overflow
will probably never happen.
Best Regards,
Petr
> }
> EXPORT_SYMBOL_GPL(trace_seq_path);
>
> --
> 2.1.1
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path()
2014-11-14 16:53 ` Petr Mladek
@ 2014-11-14 17:47 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:47 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 17:53:08 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> > /**
> > diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
> > index 3c63b619d6b7..475412e31de5 100644
> > --- a/kernel/trace/trace_seq.c
> > +++ b/kernel/trace/trace_seq.c
> > @@ -342,7 +342,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
> > return 0;
> > }
> >
> > - ret = seq_buf_path(&s->seq, path);
> > + ret = seq_buf_path(&s->seq, path, "\n");
> >
> > if (unlikely(seq_buf_has_overflowed(&s->seq))) {
> > s->seq.len = save_len;
> > @@ -350,7 +350,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
> > return 0;
> > }
> >
> > - return ret;
> > + return 1;
>
> Ah, I have just realized that this should return -1 when
> seq_buf_path() returns -1.
It really doesn't matter as long as it's not zero. The one user just
tests if the return is zero or not.
trace_seq() doesn't have to follow all the same rules as seq_buf()
does, as seq_buf() is more in line with seq_file().
>
> Note that set_buf_path() does not longer calls seq_buf_set_overflow(s)
> when the path handling fails. Therefore the above check for overflow
> will probably never happen.
This is in a transitional state of the patch series. The final version
of seq_buf_path() will call seq_buf_commit() which will put the seq_buf
in an overflow state if it isn't correct. Trying to fix this version
here will probably just cause me to make another stupid mistake and
ruin the final version ;-)
-- Steve
>
> Best Regards,
> Petr
>
> > }
> > EXPORT_SYMBOL_GPL(trace_seq_path);
> >
> > --
> > 2.1.1
> >
> >
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 15/23 v4] tracing: Convert seq_buf fields to be like seq_file fields
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (13 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 14/23 v4] tracing: Convert seq_buf_path() to be like seq_path() Steven Rostedt
@ 2014-11-14 1:12 ` Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 16/23 v4] tracing: Add a seq_buf_clear() helper and clear len and readpos in init Steven Rostedt
` (7 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0015-tracing-Convert-seq_buf-fields-to-be-like-seq_file-f.patch --]
[-- Type: text/plain, Size: 975 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
In facilitating the conversion of seq_file to use seq_buf,
have the seq_buf fields match the types used by seq_file.
Link: http://lkml.kernel.org/r/20141104160222.195301024@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 38770688a627..d14dc9023dde 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -16,10 +16,10 @@
* @readpos: The next position to read in the buffer.
*/
struct seq_buf {
- unsigned char *buffer;
- unsigned int size;
- unsigned int len;
- unsigned int readpos;
+ char *buffer;
+ size_t size;
+ size_t len;
+ loff_t readpos;
};
static inline void
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 16/23 v4] tracing: Add a seq_buf_clear() helper and clear len and readpos in init
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (14 preceding siblings ...)
2014-11-14 1:12 ` [RFC][PATCH 15/23 v4] tracing: Convert seq_buf fields to be like seq_file fields Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer Steven Rostedt
` (6 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0016-tracing-Add-a-seq_buf_clear-helper-and-clear-len-and.patch --]
[-- Type: text/plain, Size: 1114 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Add a helper function seq_buf_clear() that resets the len and readpos
fields of a seq_buf. Currently it is only used in the seq_buf_init()
but will be used later when updating the seq_file code.
Link: http://lkml.kernel.org/r/20141104160222.352309995@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index d14dc9023dde..5d91262433e2 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -22,13 +22,18 @@ struct seq_buf {
loff_t readpos;
};
+static inline void seq_buf_clear(struct seq_buf *s)
+{
+ s->len = 0;
+ s->readpos = 0;
+}
+
static inline void
seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
{
s->buffer = buf;
s->size = size;
- s->len = 0;
- s->readpos = 0;
+ seq_buf_clear(s);
}
/*
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (15 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 16/23 v4] tracing: Add a seq_buf_clear() helper and clear len and readpos in init Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 17:07 ` Petr Mladek
2014-11-14 1:13 ` [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions Steven Rostedt
` (5 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0017-tracing-Have-seq_buf-use-full-buffer.patch --]
[-- Type: text/plain, Size: 3836 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Currently seq_buf is full when all but one byte of the buffer is
filled. Change it so that the seq_buf is full when all of the
buffer is filled.
Some of the functions would fill the buffer completely and report
everything was fine. This was inconsistent with the max of size - 1.
Changing this to be max of size makes all functions consistent.
Link: http://lkml.kernel.org/r/20141104160222.502133196@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 6 +++---
kernel/trace/seq_buf.c | 19 +++++++++++--------
2 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 5d91262433e2..581c1fc733c3 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -43,13 +43,13 @@ seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
static inline bool
seq_buf_has_overflowed(struct seq_buf *s)
{
- return s->len == s->size;
+ return s->len > s->size;
}
static inline void
seq_buf_set_overflow(struct seq_buf *s)
{
- s->len = s->size;
+ s->len = s->size + 1;
}
/*
@@ -61,7 +61,7 @@ seq_buf_buffer_left(struct seq_buf *s)
if (seq_buf_has_overflowed(s))
return 0;
- return (s->size - 1) - s->len;
+ return s->size - s->len;
}
extern __printf(2, 3)
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 7dac34d1235b..9d3bb64dca31 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -17,7 +17,7 @@
#include <linux/seq_buf.h>
/* How much buffer is written? */
-#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
+#define SEQ_BUF_USED(s) min((s)->len, (s)->size)
/**
* seq_buf_print_seq - move the contents of seq_buf into a seq_file
@@ -51,7 +51,7 @@ int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
if (s->len < s->size) {
len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
- if (s->len + len < s->size) {
+ if (s->len + len <= s->size) {
s->len += len;
return 0;
}
@@ -100,8 +100,11 @@ int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
WARN_ON(s->size == 0);
/*
- * The last byte of the buffer is used to determine if we
- * overflowed or not.
+ * Note, because bitmap_scnprintf() only returns the number of bytes
+ * written and not the number that would be written, we use the last
+ * byte of the buffer to let us know if we overflowed. There's a small
+ * chance that the bitmap could have fit exactly inside the buffer, but
+ * it's not that critical if that does happen.
*/
if (len > 1) {
ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
@@ -140,7 +143,7 @@ int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
if (s->len < s->size) {
ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
- if (s->len + ret < s->size) {
+ if (s->len + ret <= s->size) {
s->len += ret;
return 0;
}
@@ -164,7 +167,7 @@ int seq_buf_puts(struct seq_buf *s, const char *str)
WARN_ON(s->size == 0);
- if (s->len + len < s->size) {
+ if (s->len + len <= s->size) {
memcpy(s->buffer + s->len, str, len);
s->len += len;
return 0;
@@ -186,7 +189,7 @@ int seq_buf_putc(struct seq_buf *s, unsigned char c)
{
WARN_ON(s->size == 0);
- if (s->len + 1 < s->size) {
+ if (s->len + 1 <= s->size) {
s->buffer[s->len++] = c;
return 0;
}
@@ -210,7 +213,7 @@ int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
{
WARN_ON(s->size == 0);
- if (s->len + len < s->size) {
+ if (s->len + len <= s->size) {
memcpy(s->buffer + s->len, mem, len);
s->len += len;
return 0;
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer
2014-11-14 1:13 ` [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer Steven Rostedt
@ 2014-11-14 17:07 ` Petr Mladek
2014-11-14 17:30 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 17:07 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:13:01, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Currently seq_buf is full when all but one byte of the buffer is
> filled. Change it so that the seq_buf is full when all of the
> buffer is filled.
>
> Some of the functions would fill the buffer completely and report
> everything was fine. This was inconsistent with the max of size - 1.
> Changing this to be max of size makes all functions consistent.
>
> Link: http://lkml.kernel.org/r/20141104160222.502133196@goodmis.org
>
> Tested-by: Jiri Kosina <jkosina@suse.cz>
> Acked-by: Jiri Kosina <jkosina@suse.cz>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Hmm, we should not apply this patch before we fix all other locations
accessing seq.len. We need to make sure that they do not access
outside of the buffer when seq.len = seq.size + 1.
See my comments for "[RFC][PATCH 13/23 v4] tracing: Create seq_buf
layer in trace_seq"
BTW: Are these patches applied in some public branch, please? The
patch series is getting long. I would like to see it applied but I do
not want to copy all the patches and apply manually :-)
Best Regards,
Petr
PS: I will need to go in a while. I am not sure that I will be able to
review the whole patchset before the weekend. I do the review in the
order of patches. I sent reply only when I had something to add. The
non-commented other patches (< 17) looks fine to me.
> ---
> include/linux/seq_buf.h | 6 +++---
> kernel/trace/seq_buf.c | 19 +++++++++++--------
> 2 files changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 5d91262433e2..581c1fc733c3 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -43,13 +43,13 @@ seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
> static inline bool
> seq_buf_has_overflowed(struct seq_buf *s)
> {
> - return s->len == s->size;
> + return s->len > s->size;
> }
>
> static inline void
> seq_buf_set_overflow(struct seq_buf *s)
> {
> - s->len = s->size;
> + s->len = s->size + 1;
> }
>
> /*
> @@ -61,7 +61,7 @@ seq_buf_buffer_left(struct seq_buf *s)
> if (seq_buf_has_overflowed(s))
> return 0;
>
> - return (s->size - 1) - s->len;
> + return s->size - s->len;
> }
>
> extern __printf(2, 3)
> diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> index 7dac34d1235b..9d3bb64dca31 100644
> --- a/kernel/trace/seq_buf.c
> +++ b/kernel/trace/seq_buf.c
> @@ -17,7 +17,7 @@
> #include <linux/seq_buf.h>
>
> /* How much buffer is written? */
> -#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
> +#define SEQ_BUF_USED(s) min((s)->len, (s)->size)
>
> /**
> * seq_buf_print_seq - move the contents of seq_buf into a seq_file
> @@ -51,7 +51,7 @@ int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
>
> if (s->len < s->size) {
> len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
> - if (s->len + len < s->size) {
> + if (s->len + len <= s->size) {
> s->len += len;
> return 0;
> }
> @@ -100,8 +100,11 @@ int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
> WARN_ON(s->size == 0);
>
> /*
> - * The last byte of the buffer is used to determine if we
> - * overflowed or not.
> + * Note, because bitmap_scnprintf() only returns the number of bytes
> + * written and not the number that would be written, we use the last
> + * byte of the buffer to let us know if we overflowed. There's a small
> + * chance that the bitmap could have fit exactly inside the buffer, but
> + * it's not that critical if that does happen.
> */
> if (len > 1) {
> ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
> @@ -140,7 +143,7 @@ int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
>
> if (s->len < s->size) {
> ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
> - if (s->len + ret < s->size) {
> + if (s->len + ret <= s->size) {
> s->len += ret;
> return 0;
> }
> @@ -164,7 +167,7 @@ int seq_buf_puts(struct seq_buf *s, const char *str)
>
> WARN_ON(s->size == 0);
>
> - if (s->len + len < s->size) {
> + if (s->len + len <= s->size) {
> memcpy(s->buffer + s->len, str, len);
> s->len += len;
> return 0;
> @@ -186,7 +189,7 @@ int seq_buf_putc(struct seq_buf *s, unsigned char c)
> {
> WARN_ON(s->size == 0);
>
> - if (s->len + 1 < s->size) {
> + if (s->len + 1 <= s->size) {
> s->buffer[s->len++] = c;
> return 0;
> }
> @@ -210,7 +213,7 @@ int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
> {
> WARN_ON(s->size == 0);
>
> - if (s->len + len < s->size) {
> + if (s->len + len <= s->size) {
> memcpy(s->buffer + s->len, mem, len);
> s->len += len;
> return 0;
> --
> 2.1.1
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer
2014-11-14 17:07 ` Petr Mladek
@ 2014-11-14 17:30 ` Steven Rostedt
2014-11-14 20:56 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:30 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 18:07:16 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> On Thu 2014-11-13 20:13:01, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > Currently seq_buf is full when all but one byte of the buffer is
> > filled. Change it so that the seq_buf is full when all of the
> > buffer is filled.
> >
> > Some of the functions would fill the buffer completely and report
> > everything was fine. This was inconsistent with the max of size - 1.
> > Changing this to be max of size makes all functions consistent.
> >
> > Link: http://lkml.kernel.org/r/20141104160222.502133196@goodmis.org
> >
> > Tested-by: Jiri Kosina <jkosina@suse.cz>
> > Acked-by: Jiri Kosina <jkosina@suse.cz>
> > Reviewed-by: Petr Mladek <pmladek@suse.cz>
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
>
> Hmm, we should not apply this patch before we fix all other locations
> accessing seq.len. We need to make sure that they do not access
> outside of the buffer when seq.len = seq.size + 1.
>
> See my comments for "[RFC][PATCH 13/23 v4] tracing: Create seq_buf
> layer in trace_seq"
I agree. As I replied there, I'll add a patch before this gets applied
(right after seq_buf_left() is introduced), that will fix those issues.
>
> BTW: Are these patches applied in some public branch, please? The
> patch series is getting long. I would like to see it applied but I do
> not want to copy all the patches and apply manually :-)
I'll start pushing them up to my repo under rfc/seq-buf
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
That branch will always be rebasing. I have it applied on top of my
ftrace/core branch that will become my next for-next soon (after it
passes all my tests).
>
> Best Regards,
> Petr
>
> PS: I will need to go in a while. I am not sure that I will be able to
> review the whole patchset before the weekend. I do the review in the
> order of patches. I sent reply only when I had something to add. The
> non-commented other patches (< 17) looks fine to me.
Thanks, I'll add your Reviewed-by tags on them.
To ease the pain of review, I'll reply to your email comments with the
patches as I fix them up (as I've already done). I'll keep the commit
ids as well so that you can verify them. I'll try to remember to
constantly update my rfc/seq-buf branch.
Thanks a lot for your reviews. I really do appreciate it.
-- Steve
^ permalink raw reply [flat|nested] 58+ messages in thread
* Re: [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer
2014-11-14 17:30 ` Steven Rostedt
@ 2014-11-14 20:56 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 20:56 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 12:30:01 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> > Hmm, we should not apply this patch before we fix all other locations
> > accessing seq.len. We need to make sure that they do not access
> > outside of the buffer when seq.len = seq.size + 1.
> >
> > See my comments for "[RFC][PATCH 13/23 v4] tracing: Create seq_buf
> > layer in trace_seq"
>
> I agree. As I replied there, I'll add a patch before this gets applied
> (right after seq_buf_left() is introduced), that will fix those issues.
I made the move of seq_buf_used() before the full buffer usage patch,
and here's a patch I added.
I'll be posting a v5 with all these changes too, but this may make it
easier to review:
-- Steve
>From a43da42e939ba41a32c7ea83793cef9c2360ec1a Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Fri, 14 Nov 2014 15:49:41 -0500
Subject: [PATCH] tracing: Use trace_seq_used() and seq_buf_used() instead of
len
As the seq_buf->len will soon be +1 size when there's an overflow, we
must use trace_seq_used() or seq_buf_used() methods to get the real
length. This will prevent buffer overflow issues if just the len
of the seq_buf descriptor is used to copy memory.
Link: http://lkml.kernel.org/r/20141114121911.09ba3d38@gandalf.local.home
Reported-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/trace_seq.h | 20 +++++++++++++++-
kernel/trace/trace.c | 44 ++++++++++++++++++++++++------------
kernel/trace/trace_events.c | 9 +++++---
kernel/trace/trace_functions_graph.c | 5 +++-
kernel/trace/trace_seq.c | 2 +-
5 files changed, 59 insertions(+), 21 deletions(-)
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 85d37106be3d..cfaf5a1d4bad 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -24,6 +24,24 @@ trace_seq_init(struct trace_seq *s)
}
/**
+ * trace_seq_used - amount of actual data written to buffer
+ * @s: trace sequence descriptor
+ *
+ * Returns the amount of data written to the buffer.
+ *
+ * IMPORTANT!
+ *
+ * Use this instead of @s->seq.len if you need to pass the amount
+ * of data from the buffer to another buffer (userspace, or what not).
+ * The @s->seq.len on overflow is bigger than the buffer size and
+ * using it can cause access to undefined memory.
+ */
+static inline int trace_seq_used(struct trace_seq *s)
+{
+ return seq_buf_used(&s->seq);
+}
+
+/**
* trace_seq_buffer_ptr - return pointer to next location in buffer
* @s: trace sequence descriptor
*
@@ -35,7 +53,7 @@ trace_seq_init(struct trace_seq *s)
static inline unsigned char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
- return s->buffer + s->seq.len;
+ return s->buffer + seq_buf_used(&s->seq);
}
/**
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7d7a07e9b9e9..9f1ffc707f3b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -944,10 +944,10 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
- if (s->seq.len <= s->seq.readpos)
+ if (trace_seq_used(s) <= s->seq.readpos)
return -EBUSY;
- len = s->seq.len - s->seq.readpos;
+ len = trace_seq_used(s) - s->seq.readpos;
if (cnt > len)
cnt = len;
memcpy(buf, s->buffer + s->seq.readpos, cnt);
@@ -4514,18 +4514,18 @@ waitagain:
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
- int len = iter->seq.seq.len;
+ int save_len = iter->seq.seq.len;
ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
- iter->seq.seq.len = len;
+ iter->seq.seq.len = save_len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
- if (iter->seq.seq.len >= cnt)
+ if (trace_seq_used(&iter->seq) >= cnt)
break;
/*
@@ -4541,7 +4541,7 @@ waitagain:
/* Now copy what we have to the user */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
- if (iter->seq.seq.readpos >= iter->seq.seq.len)
+ if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
trace_seq_init(&iter->seq);
/*
@@ -4575,20 +4575,33 @@ static size_t
tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
{
size_t count;
+ int save_len;
int ret;
/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
- count = iter->seq.seq.len;
+ save_len = iter->seq.seq.len;
ret = print_trace_line(iter);
- count = iter->seq.seq.len - count;
- if (rem < count) {
- rem = 0;
- iter->seq.seq.len -= count;
+
+ if (trace_seq_has_overflowed(&iter->seq)) {
+ iter->seq.seq.len = save_len;
break;
}
+
+ /*
+ * This should not be hit, because it should only
+ * be set if the iter->seq overflowed. But check it
+ * anyway to be safe.
+ */
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- iter->seq.seq.len -= count;
+ iter->seq.seq.len = save_len;
+ break;
+ }
+
+ count = trace_seq_used(&iter->seq) - save_len;
+ if (rem < count) {
+ rem = 0;
+ iter->seq.seq.len = save_len;;
break;
}
@@ -4669,13 +4682,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
/* Copy the data into the page, so we can start over. */
ret = trace_seq_to_buffer(&iter->seq,
page_address(spd.pages[i]),
- iter->seq.seq.len);
+ trace_seq_used(&iter->seq));
if (ret < 0) {
__free_page(spd.pages[i]);
break;
}
spd.partial[i].offset = 0;
- spd.partial[i].len = iter->seq.seq.len;
+ spd.partial[i].len = trace_seq_used(&iter->seq);
trace_seq_init(&iter->seq);
}
@@ -5676,7 +5689,8 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "read events: %ld\n", cnt);
- count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);
+ count = simple_read_from_buffer(ubuf, count, ppos,
+ s->buffer, trace_seq_used(s));
kfree(s);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 4d0067dd7f88..935cbea78532 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1044,7 +1044,8 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
mutex_unlock(&event_mutex);
if (file)
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos,
+ s->buffer, trace_seq_used(s));
kfree(s);
@@ -1210,7 +1211,8 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);
print_subsystem_event_filter(system, s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos,
+ s->buffer, trace_seq_used(s));
kfree(s);
@@ -1265,7 +1267,8 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
trace_seq_init(s);
func(s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos,
+ s->buffer, trace_seq_used(s));
kfree(s);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 6d1342ae7a44..ec35468349a7 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1153,6 +1153,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
return ret;
}
+ if (trace_seq_has_overflowed(s))
+ goto out;
+
/* Strip ending newline */
if (s->buffer[s->seq.len - 1] == '\n') {
s->buffer[s->seq.len - 1] = '\0';
@@ -1160,7 +1163,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
}
trace_seq_puts(s, " */\n");
-
+ out:
return trace_handle_return(s);
}
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 087fa514069d..0c7aab4dd94f 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -30,7 +30,7 @@
#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) min((s)->seq.len, (unsigned int)(PAGE_SIZE - 1))
+#define TRACE_SEQ_BUF_USED(s) seq_buf_used(&(s)->seq)
/*
* trace_seq should work with being initialized with 0s.
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (16 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 17/23 v4] tracing: Have seq_buf use full buffer Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 17:18 ` Petr Mladek
2014-11-14 1:13 ` [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written Steven Rostedt
` (4 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0018-tracing-Add-seq_buf_get_buf-and-seq_buf_commit-helpe.patch --]
[-- Type: text/plain, Size: 2791 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that
are used by seq_buf_path(). This makes the code similar to the
seq_file: seq_path() function, and will help to be able to consolidate
the functions between seq_file and trace_seq.
Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 40 ++++++++++++++++++++++++++++++++++++++++
kernel/trace/seq_buf.c | 7 +++----
2 files changed, 43 insertions(+), 4 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 581c1fc733c3..3e550d214187 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -64,6 +64,46 @@ seq_buf_buffer_left(struct seq_buf *s)
return s->size - s->len;
}
+/**
+ * seq_buf_get_buf - get buffer to write arbitrary data to
+ * @s: the seq_buf handle
+ * @bufp: the beginning of the buffer is stored here
+ *
+ * Return the number of bytes available in the buffer, or zero if
+ * there's no space.
+ */
+static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
+{
+ WARN_ON(s->len > s->size + 1);
+
+ if (s->len < s->size) {
+ *bufp = s->buffer + s->len;
+ return s->size - s->len;
+ }
+
+ *bufp = NULL;
+ return 0;
+}
+
+/**
+ * seq_buf_commit - commit data to the buffer
+ * @s: the seq_buf handle
+ * @num: the number of bytes to commit
+ *
+ * Commit @num bytes of data written to a buffer previously acquired
+ * by seq_buf_get. To signal an error condition, or that the data
+ * didn't fit in the available space, pass a negative @num value.
+ */
+static inline void seq_buf_commit(struct seq_buf *s, int num)
+{
+ if (num < 0) {
+ seq_buf_set_overflow(s);
+ } else {
+ BUG_ON(s->len + num > s->size + 1);
+ s->len += num;
+ }
+}
+
extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 9d3bb64dca31..4f35a783b82f 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -283,8 +283,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
*/
int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
- char *buf = s->buffer + s->len;
- size_t size = seq_buf_buffer_left(s);
+ char *buf;
+ size_t size = seq_buf_get_buf(s, &buf);
int res = -1;
WARN_ON(s->size == 0);
@@ -297,8 +297,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
res = end - buf;
}
}
- if (res > 0)
- s->len += res;
+ seq_buf_commit(s, res);
return res;
}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions
2014-11-14 1:13 ` [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions Steven Rostedt
@ 2014-11-14 17:18 ` Petr Mladek
2014-11-14 20:31 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 17:18 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:13:02, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that
> are used by seq_buf_path(). This makes the code similar to the
> seq_file: seq_path() function, and will help to be able to consolidate
> the functions between seq_file and trace_seq.
>
> Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org
>
> Tested-by: Jiri Kosina <jkosina@suse.cz>
> Acked-by: Jiri Kosina <jkosina@suse.cz>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> include/linux/seq_buf.h | 40 ++++++++++++++++++++++++++++++++++++++++
> kernel/trace/seq_buf.c | 7 +++----
> 2 files changed, 43 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 581c1fc733c3..3e550d214187 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -64,6 +64,46 @@ seq_buf_buffer_left(struct seq_buf *s)
> return s->size - s->len;
> }
>
> +/**
> + * seq_buf_get_buf - get buffer to write arbitrary data to
> + * @s: the seq_buf handle
> + * @bufp: the beginning of the buffer is stored here
> + *
> + * Return the number of bytes available in the buffer, or zero if
> + * there's no space.
> + */
> +static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
> +{
> + WARN_ON(s->len > s->size + 1);
> +
> + if (s->len < s->size) {
> + *bufp = s->buffer + s->len;
> + return s->size - s->len;
> + }
> +
> + *bufp = NULL;
> + return 0;
> +}
> +
> +/**
> + * seq_buf_commit - commit data to the buffer
> + * @s: the seq_buf handle
> + * @num: the number of bytes to commit
> + *
> + * Commit @num bytes of data written to a buffer previously acquired
> + * by seq_buf_get. To signal an error condition, or that the data
> + * didn't fit in the available space, pass a negative @num value.
> + */
> +static inline void seq_buf_commit(struct seq_buf *s, int num)
> +{
> + if (num < 0) {
> + seq_buf_set_overflow(s);
> + } else {
> + BUG_ON(s->len + num > s->size + 1);
I thought about it more and we should probably do
BUG_ON(s->len + num > s->size);
"size + 1" signalizes that there was an overflow. It is a valid
value for the "len" variable. But it is not valid to commit "size + 1"
bytes into the buffer. It would mean access outside of the buffer.
What do you think, please?
Best Regards,
Petr
PS: Sigh, I wish, I saw all this problems during the first review and not
triggering another patchset version.
> + s->len += num;
> + }
> +}
> +
> extern __printf(2, 3)
> int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
> extern __printf(2, 0)
> diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> index 9d3bb64dca31..4f35a783b82f 100644
> --- a/kernel/trace/seq_buf.c
> +++ b/kernel/trace/seq_buf.c
> @@ -283,8 +283,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
> */
> int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
> {
> - char *buf = s->buffer + s->len;
> - size_t size = seq_buf_buffer_left(s);
> + char *buf;
> + size_t size = seq_buf_get_buf(s, &buf);
> int res = -1;
>
> WARN_ON(s->size == 0);
> @@ -297,8 +297,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
> res = end - buf;
> }
> }
> - if (res > 0)
> - s->len += res;
> + seq_buf_commit(s, res);
>
> return res;
> }
> --
> 2.1.1
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions
2014-11-14 17:18 ` Petr Mladek
@ 2014-11-14 20:31 ` Steven Rostedt
2014-11-14 20:58 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 20:31 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 18:18:28 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> On Thu 2014-11-13 20:13:02, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that
> > are used by seq_buf_path(). This makes the code similar to the
> > seq_file: seq_path() function, and will help to be able to consolidate
> > the functions between seq_file and trace_seq.
> >
> > Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org
> >
> > Tested-by: Jiri Kosina <jkosina@suse.cz>
> > Acked-by: Jiri Kosina <jkosina@suse.cz>
> > Reviewed-by: Petr Mladek <pmladek@suse.cz>
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > include/linux/seq_buf.h | 40 ++++++++++++++++++++++++++++++++++++++++
> > kernel/trace/seq_buf.c | 7 +++----
> > 2 files changed, 43 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> > index 581c1fc733c3..3e550d214187 100644
> > --- a/include/linux/seq_buf.h
> > +++ b/include/linux/seq_buf.h
> > @@ -64,6 +64,46 @@ seq_buf_buffer_left(struct seq_buf *s)
> > return s->size - s->len;
> > }
> >
> > +/**
> > + * seq_buf_get_buf - get buffer to write arbitrary data to
> > + * @s: the seq_buf handle
> > + * @bufp: the beginning of the buffer is stored here
> > + *
> > + * Return the number of bytes available in the buffer, or zero if
> > + * there's no space.
> > + */
> > +static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
> > +{
> > + WARN_ON(s->len > s->size + 1);
> > +
> > + if (s->len < s->size) {
> > + *bufp = s->buffer + s->len;
> > + return s->size - s->len;
> > + }
> > +
> > + *bufp = NULL;
> > + return 0;
> > +}
> > +
> > +/**
> > + * seq_buf_commit - commit data to the buffer
> > + * @s: the seq_buf handle
> > + * @num: the number of bytes to commit
> > + *
> > + * Commit @num bytes of data written to a buffer previously acquired
> > + * by seq_buf_get. To signal an error condition, or that the data
> > + * didn't fit in the available space, pass a negative @num value.
> > + */
> > +static inline void seq_buf_commit(struct seq_buf *s, int num)
> > +{
> > + if (num < 0) {
> > + seq_buf_set_overflow(s);
> > + } else {
> > + BUG_ON(s->len + num > s->size + 1);
>
> I thought about it more and we should probably do
>
> BUG_ON(s->len + num > s->size);
>
> "size + 1" signalizes that there was an overflow. It is a valid
> value for the "len" variable. But it is not valid to commit "size + 1"
> bytes into the buffer. It would mean access outside of the buffer.
>
> What do you think, please?
I don't see anything wrong with committing an overflowed state.
Note, seq_commit() allows an overflow number to go in too. But of
course that's where overflow is still on the buffer.
Hmm, I guess I can still make this change. The seq_commit() comment
states that @num needs to be < 0 if the data did not fit, and if it is
in overflow state, then it should be -1 not size + 1 (or size for the
old way).
-- Steve
>
> Best Regards,
> Petr
>
> PS: Sigh, I wish, I saw all this problems during the first review and not
> triggering another patchset version.
>
>
> > + s->len += num;
> > + }
> > +}
> > +
> > extern __printf(2, 3)
> > int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
> > extern __printf(2, 0)
> > diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> > index 9d3bb64dca31..4f35a783b82f 100644
> > --- a/kernel/trace/seq_buf.c
> > +++ b/kernel/trace/seq_buf.c
> > @@ -283,8 +283,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
> > */
> > int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
> > {
> > - char *buf = s->buffer + s->len;
> > - size_t size = seq_buf_buffer_left(s);
> > + char *buf;
> > + size_t size = seq_buf_get_buf(s, &buf);
> > int res = -1;
> >
> > WARN_ON(s->size == 0);
> > @@ -297,8 +297,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
> > res = end - buf;
> > }
> > }
> > - if (res > 0)
> > - s->len += res;
> > + seq_buf_commit(s, res);
> >
> > return res;
> > }
> > --
> > 2.1.1
> >
> >
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions
2014-11-14 20:31 ` Steven Rostedt
@ 2014-11-14 20:58 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 20:58 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 15:31:23 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> Hmm, I guess I can still make this change. The seq_commit() comment
> states that @num needs to be < 0 if the data did not fit, and if it is
> in overflow state, then it should be -1 not size + 1 (or size for the
> old way).
I made the change, and here it is:
-- Steve
>From 69488bad76c4af9f9b5948c8990b5ed1196b2bc1 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 29 Oct 2014 17:30:50 -0400
Subject: [PATCH] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper
functions
Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that
are used by seq_buf_path(). This makes the code similar to the
seq_file: seq_path() function, and will help to be able to consolidate
the functions between seq_file and trace_seq.
Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org
Link: http://lkml.kernel.org/r/20141114011412.977571447@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 41 +++++++++++++++++++++++++++++++++++++++++
kernel/trace/seq_buf.c | 7 +++----
2 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 0800a24b4348..12c64282aa98 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -70,6 +70,47 @@ static inline unsigned int seq_buf_used(struct seq_buf *s)
return min(s->len, s->size);
}
+/**
+ * seq_buf_get_buf - get buffer to write arbitrary data to
+ * @s: the seq_buf handle
+ * @bufp: the beginning of the buffer is stored here
+ *
+ * Return the number of bytes available in the buffer, or zero if
+ * there's no space.
+ */
+static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
+{
+ WARN_ON(s->len > s->size + 1);
+
+ if (s->len < s->size) {
+ *bufp = s->buffer + s->len;
+ return s->size - s->len;
+ }
+
+ *bufp = NULL;
+ return 0;
+}
+
+/**
+ * seq_buf_commit - commit data to the buffer
+ * @s: the seq_buf handle
+ * @num: the number of bytes to commit
+ *
+ * Commit @num bytes of data written to a buffer previously acquired
+ * by seq_buf_get. To signal an error condition, or that the data
+ * didn't fit in the available space, pass a negative @num value.
+ */
+static inline void seq_buf_commit(struct seq_buf *s, int num)
+{
+ if (num < 0) {
+ seq_buf_set_overflow(s);
+ } else {
+ /* num must be negative on overflow */
+ BUG_ON(s->len + num > s->size);
+ s->len += num;
+ }
+}
+
extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 86e50f47894b..3657af4b5f53 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -280,8 +280,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
*/
int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
- char *buf = s->buffer + s->len;
- size_t size = seq_buf_buffer_left(s);
+ char *buf;
+ size_t size = seq_buf_get_buf(s, &buf);
int res = -1;
WARN_ON(s->size == 0);
@@ -294,8 +294,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
res = end - buf;
}
}
- if (res > 0)
- s->len += res;
+ seq_buf_commit(s, res);
return res;
}
--
1.8.1.4
^ permalink raw reply related [flat|nested] 58+ messages in thread
* [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (17 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 18/23 v4] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 17:23 ` Petr Mladek
2014-11-14 1:13 ` [RFC][PATCH 20/23 v4] seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF Steven Rostedt
` (3 subsequent siblings)
22 siblings, 1 reply; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0019-seq_buf-Create-seq_buf_used-to-find-out-how-much-was.patch --]
[-- Type: text/plain, Size: 1553 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Add a helper function seq_buf_used() that replaces the SEQ_BUF_USED()
private macro to let callers have a method to know how much of the
seq_buf was written to.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 6 ++++++
kernel/trace/seq_buf.c | 5 +----
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 3e550d214187..8fda502ee630 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -64,6 +64,12 @@ seq_buf_buffer_left(struct seq_buf *s)
return s->size - s->len;
}
+/* How much buffer was written? */
+static inline unsigned int seq_buf_used(struct seq_buf *s)
+{
+ return min((s)->len, (s)->size);
+}
+
/**
* seq_buf_get_buf - get buffer to write arbitrary data to
* @s: the seq_buf handle
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 4f35a783b82f..3657af4b5f53 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -16,9 +16,6 @@
#include <linux/seq_file.h>
#include <linux/seq_buf.h>
-/* How much buffer is written? */
-#define SEQ_BUF_USED(s) min((s)->len, (s)->size)
-
/**
* seq_buf_print_seq - move the contents of seq_buf into a seq_file
* @m: the seq_file descriptor that is the destination
@@ -28,7 +25,7 @@
*/
int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
{
- unsigned int len = SEQ_BUF_USED(s);
+ unsigned int len = seq_buf_used(s);
return seq_write(m, s->buffer, len);
}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written
2014-11-14 1:13 ` [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written Steven Rostedt
@ 2014-11-14 17:23 ` Petr Mladek
2014-11-14 17:34 ` Steven Rostedt
0 siblings, 1 reply; 58+ messages in thread
From: Petr Mladek @ 2014-11-14 17:23 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Thu 2014-11-13 20:13:03, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> Add a helper function seq_buf_used() that replaces the SEQ_BUF_USED()
> private macro to let callers have a method to know how much of the
> seq_buf was written to.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
The patch is correct. But we should move it before "[RFC][PATCH 17/23
v4] tracing: Have seq_buf use full buffer" and use it everywhere
any code is accessing the internal buffer using the seq.len value.
I mean to solve the potential buffer overflows mentioned for
"[RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq"
Best Regards,
Petr
> ---
> include/linux/seq_buf.h | 6 ++++++
> kernel/trace/seq_buf.c | 5 +----
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 3e550d214187..8fda502ee630 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -64,6 +64,12 @@ seq_buf_buffer_left(struct seq_buf *s)
> return s->size - s->len;
> }
>
> +/* How much buffer was written? */
> +static inline unsigned int seq_buf_used(struct seq_buf *s)
> +{
> + return min((s)->len, (s)->size);
> +}
> +
> /**
> * seq_buf_get_buf - get buffer to write arbitrary data to
> * @s: the seq_buf handle
> diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
> index 4f35a783b82f..3657af4b5f53 100644
> --- a/kernel/trace/seq_buf.c
> +++ b/kernel/trace/seq_buf.c
> @@ -16,9 +16,6 @@
> #include <linux/seq_file.h>
> #include <linux/seq_buf.h>
>
> -/* How much buffer is written? */
> -#define SEQ_BUF_USED(s) min((s)->len, (s)->size)
> -
> /**
> * seq_buf_print_seq - move the contents of seq_buf into a seq_file
> * @m: the seq_file descriptor that is the destination
> @@ -28,7 +25,7 @@
> */
> int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
> {
> - unsigned int len = SEQ_BUF_USED(s);
> + unsigned int len = seq_buf_used(s);
>
> return seq_write(m, s->buffer, len);
> }
> --
> 2.1.1
>
>
^ permalink raw reply [flat|nested] 58+ messages in thread* Re: [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written
2014-11-14 17:23 ` Petr Mladek
@ 2014-11-14 17:34 ` Steven Rostedt
0 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 17:34 UTC (permalink / raw)
To: Petr Mladek; +Cc: linux-kernel, Ingo Molnar, Andrew Morton, Jiri Kosina
On Fri, 14 Nov 2014 18:23:06 +0100
Petr Mladek <pmladek@suse.cz> wrote:
> On Thu 2014-11-13 20:13:03, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > Add a helper function seq_buf_used() that replaces the SEQ_BUF_USED()
> > private macro to let callers have a method to know how much of the
> > seq_buf was written to.
> >
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
>
> Reviewed-by: Petr Mladek <pmladek@suse.cz>
>
> The patch is correct. But we should move it before "[RFC][PATCH 17/23
> v4] tracing: Have seq_buf use full buffer" and use it everywhere
> any code is accessing the internal buffer using the seq.len value.
> I mean to solve the potential buffer overflows mentioned for
> "[RFC][PATCH 13/23 v4] tracing: Create seq_buf layer in trace_seq"
>
> Best Regards,
Bah, I'm getting seq_buf_buffer_left() confused with seq_buf_used().
Yes, this should be moved before hand. I thought it was by looking at:
git show <patch-17-SHA1>:include/linux/seq_buf.h
I saw the seq_buf_buffer_left() and confused that with seq_buf_used()
and said to myself "oh good, it has the function I need". Not!
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 58+ messages in thread
* [RFC][PATCH 20/23 v4] seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (18 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 19/23 v4] seq_buf: Create seq_buf_used() to find out how much was written Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 21/23 v4] seq_buf: Move the seq_buf code to lib/ Steven Rostedt
` (2 subsequent siblings)
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0020-seq-buf-Make-seq_buf_bprintf-conditional-on-CONFIG_B.patch --]
[-- Type: text/plain, Size: 2612 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The function bstr_printf() from lib/vsprnintf.c is only available if
CONFIG_BINARY_PRINTF is defined. This is due to the only user currently
being the tracing infrastructure, which needs to select this config
when tracing is configured. Until there is another user of the binary
printf formats, this will continue to be the case.
Since seq_buf.c is now lives in lib/ and is compiled even without
tracing, it must encompass its use of bstr_printf() which is used
by seq_buf_printf(). This too is only used by the tracing infrastructure
and is still encapsulated by the CONFIG_BINARY_PRINTF.
Link: http://lkml.kernel.org/r/20141104160222.969013383@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 7 +++++--
kernel/trace/seq_buf.c | 2 ++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 8fda502ee630..da211dfbcebe 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -114,8 +114,6 @@ extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
-extern int
-seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
int cnt);
@@ -129,4 +127,9 @@ extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *
extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
int nmaskbits);
+#ifdef CONFIG_BINARY_PRINTF
+extern int
+seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
+#endif
+
#endif /* _LINUX_SEQ_BUF_H */
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 3657af4b5f53..84b6377df827 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -114,6 +114,7 @@ int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
return -1;
}
+#ifdef CONFIG_BINARY_PRINTF
/**
* seq_buf_bprintf - Write the printf string from binary arguments
* @s: seq_buf descriptor
@@ -148,6 +149,7 @@ int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
seq_buf_set_overflow(s);
return -1;
}
+#endif /* CONFIG_BINARY_PRINTF */
/**
* seq_buf_puts - sequence printing of simple string
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 21/23 v4] seq_buf: Move the seq_buf code to lib/
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (19 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 20/23 v4] seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 22/23 v4] printk: Add per_cpu printk func to allow printk to be diverted Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 23/23 v4] x86/nmi: Perform a safe NMI stack trace on all CPUs Steven Rostedt
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek
[-- Attachment #1: 0021-seq_buf-Move-the-seq_buf-code-to-lib.patch --]
[-- Type: text/plain, Size: 21003 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The seq_buf functions are rather useful outside of tracing. Instead
of having it be dependent on CONFIG_TRACING, move the code into lib/
and allow other users to have access to it even when tracing is not
configured.
The seq_buf utility is similar to the seq_file utility, but instead of
writing sending data back up to userland, it writes it into a buffer
defined at seq_buf_init(). This allows us to send a descriptor around
that writes printf() formatted strings into it that can be retrieved
later.
It is currently used by the tracing facility for such things like trace
events to convert its binary saved data in the ring buffer into an
ASCII human readable context to be displayed in /sys/kernel/debug/trace.
It can also be used for doing NMI prints safely from NMI context into
the seq_buf and retrieved later and dumped to printk() safely. Doing
printk() from an NMI context is dangerous because an NMI can preempt
a current printk() and deadlock on it.
Link: http://lkml.kernel.org/p/20140619213952.058255809@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/Makefile | 1 -
kernel/trace/seq_buf.c | 346 -------------------------------------------------
lib/Makefile | 2 +-
lib/seq_buf.c | 346 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 347 insertions(+), 348 deletions(-)
delete mode 100644 kernel/trace/seq_buf.c
create mode 100644 lib/seq_buf.c
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index edc98c72a634..67d6369ddf83 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -29,7 +29,6 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
-obj-$(CONFIG_TRACING) += seq_buf.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
deleted file mode 100644
index 84b6377df827..000000000000
--- a/kernel/trace/seq_buf.c
+++ /dev/null
@@ -1,346 +0,0 @@
-/*
- * seq_buf.c
- *
- * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
- *
- * The seq_buf is a handy tool that allows you to pass a descriptor around
- * to a buffer that other functions can write to. It is similar to the
- * seq_file functionality but has some differences.
- *
- * To use it, the seq_buf must be initialized with seq_buf_init().
- * This will set up the counters within the descriptor. You can call
- * seq_buf_init() more than once to reset the seq_buf to start
- * from scratch.
- */
-#include <linux/uaccess.h>
-#include <linux/seq_file.h>
-#include <linux/seq_buf.h>
-
-/**
- * seq_buf_print_seq - move the contents of seq_buf into a seq_file
- * @m: the seq_file descriptor that is the destination
- * @s: the seq_buf descriptor that is the source.
- *
- * Returns zero on success, non zero otherwise
- */
-int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
-{
- unsigned int len = seq_buf_used(s);
-
- return seq_write(m, s->buffer, len);
-}
-
-/**
- * seq_buf_vprintf - sequence printing of information.
- * @s: seq_buf descriptor
- * @fmt: printf format string
- * @args: va_list of arguments from a printf() type function
- *
- * Writes a vnprintf() format into the sequencce buffer.
- *
- * Returns zero on success, -1 on overflow.
- */
-int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
-{
- int len;
-
- WARN_ON(s->size == 0);
-
- if (s->len < s->size) {
- len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
- if (s->len + len <= s->size) {
- s->len += len;
- return 0;
- }
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-
-/**
- * seq_buf_printf - sequence printing of information
- * @s: seq_buf descriptor
- * @fmt: printf format string
- *
- * Writes a printf() format into the sequence buffer.
- *
- * Returns zero on success, -1 on overflow.
- */
-int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
-{
- va_list ap;
- int ret;
-
- va_start(ap, fmt);
- ret = seq_buf_vprintf(s, fmt, ap);
- va_end(ap);
-
- return ret;
-}
-
-/**
- * seq_buf_bitmask - write a bitmask array in its ASCII representation
- * @s: seq_buf descriptor
- * @maskp: points to an array of unsigned longs that represent a bitmask
- * @nmaskbits: The number of bits that are valid in @maskp
- *
- * Writes a ASCII representation of a bitmask string into @s.
- *
- * Returns zero on success, -1 on overflow.
- */
-int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
- int nmaskbits)
-{
- unsigned int len = seq_buf_buffer_left(s);
- int ret;
-
- WARN_ON(s->size == 0);
-
- /*
- * Note, because bitmap_scnprintf() only returns the number of bytes
- * written and not the number that would be written, we use the last
- * byte of the buffer to let us know if we overflowed. There's a small
- * chance that the bitmap could have fit exactly inside the buffer, but
- * it's not that critical if that does happen.
- */
- if (len > 1) {
- ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
- if (ret < len) {
- s->len += ret;
- return 0;
- }
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-
-#ifdef CONFIG_BINARY_PRINTF
-/**
- * seq_buf_bprintf - Write the printf string from binary arguments
- * @s: seq_buf descriptor
- * @fmt: The format string for the @binary arguments
- * @binary: The binary arguments for @fmt.
- *
- * When recording in a fast path, a printf may be recorded with just
- * saving the format and the arguments as they were passed to the
- * function, instead of wasting cycles converting the arguments into
- * ASCII characters. Instead, the arguments are saved in a 32 bit
- * word array that is defined by the format string constraints.
- *
- * This function will take the format and the binary array and finish
- * the conversion into the ASCII string within the buffer.
- *
- * Returns zero on success, -1 on overflow.
- */
-int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
-{
- unsigned int len = seq_buf_buffer_left(s);
- int ret;
-
- WARN_ON(s->size == 0);
-
- if (s->len < s->size) {
- ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
- if (s->len + ret <= s->size) {
- s->len += ret;
- return 0;
- }
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-#endif /* CONFIG_BINARY_PRINTF */
-
-/**
- * seq_buf_puts - sequence printing of simple string
- * @s: seq_buf descriptor
- * @str: simple string to record
- *
- * Copy a simple string into the sequence buffer.
- *
- * Returns zero on success, -1 on overflow
- */
-int seq_buf_puts(struct seq_buf *s, const char *str)
-{
- unsigned int len = strlen(str);
-
- WARN_ON(s->size == 0);
-
- if (s->len + len <= s->size) {
- memcpy(s->buffer + s->len, str, len);
- s->len += len;
- return 0;
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-
-/**
- * seq_buf_putc - sequence printing of simple character
- * @s: seq_buf descriptor
- * @c: simple character to record
- *
- * Copy a single character into the sequence buffer.
- *
- * Returns zero on success, -1 on overflow
- */
-int seq_buf_putc(struct seq_buf *s, unsigned char c)
-{
- WARN_ON(s->size == 0);
-
- if (s->len + 1 <= s->size) {
- s->buffer[s->len++] = c;
- return 0;
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-
-/**
- * seq_buf_putmem - write raw data into the sequenc buffer
- * @s: seq_buf descriptor
- * @mem: The raw memory to copy into the buffer
- * @len: The length of the raw memory to copy (in bytes)
- *
- * There may be cases where raw memory needs to be written into the
- * buffer and a strcpy() would not work. Using this function allows
- * for such cases.
- *
- * Returns zero on success, -1 on overflow
- */
-int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
-{
- WARN_ON(s->size == 0);
-
- if (s->len + len <= s->size) {
- memcpy(s->buffer + s->len, mem, len);
- s->len += len;
- return 0;
- }
- seq_buf_set_overflow(s);
- return -1;
-}
-
-#define MAX_MEMHEX_BYTES 8U
-#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
-
-/**
- * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
- * @s: seq_buf descriptor
- * @mem: The raw memory to write its hex ASCII representation of
- * @len: The length of the raw memory to copy (in bytes)
- *
- * This is similar to seq_buf_putmem() except instead of just copying the
- * raw memory into the buffer it writes its ASCII representation of it
- * in hex characters.
- *
- * Returns zero on success, -1 on overflow
- */
-int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
- unsigned int len)
-{
- unsigned char hex[HEX_CHARS];
- const unsigned char *data = mem;
- unsigned int start_len;
- int i, j;
-
- WARN_ON(s->size == 0);
-
- while (len) {
- start_len = min(len, HEX_CHARS - 1);
-#ifdef __BIG_ENDIAN
- for (i = 0, j = 0; i < start_len; i++) {
-#else
- for (i = start_len-1, j = 0; i >= 0; i--) {
-#endif
- hex[j++] = hex_asc_hi(data[i]);
- hex[j++] = hex_asc_lo(data[i]);
- }
- if (WARN_ON_ONCE(j == 0 || j/2 > len))
- break;
-
- /* j increments twice per loop */
- len -= j / 2;
- hex[j++] = ' ';
-
- seq_buf_putmem(s, hex, j);
- if (seq_buf_has_overflowed(s))
- return -1;
- }
- return 0;
-}
-
-/**
- * seq_buf_path - copy a path into the sequence buffer
- * @s: seq_buf descriptor
- * @path: path to write into the sequence buffer.
- * @esc: set of characters to escape in the output
- *
- * Write a path name into the sequence buffer.
- *
- * Returns the number of written bytes on success, -1 on overflow
- */
-int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
-{
- char *buf;
- size_t size = seq_buf_get_buf(s, &buf);
- int res = -1;
-
- WARN_ON(s->size == 0);
-
- if (size) {
- char *p = d_path(path, buf, size);
- if (!IS_ERR(p)) {
- char *end = mangle_path(buf, p, esc);
- if (end)
- res = end - buf;
- }
- }
- seq_buf_commit(s, res);
-
- return res;
-}
-
-/**
- * seq_buf_to_user - copy the squence buffer to user space
- * @s: seq_buf descriptor
- * @ubuf: The userspace memory location to copy to
- * @cnt: The amount to copy
- *
- * Copies the sequence buffer into the userspace memory pointed to
- * by @ubuf. It starts from the last read position (@s->readpos)
- * and writes up to @cnt characters or till it reaches the end of
- * the content in the buffer (@s->len), which ever comes first.
- *
- * On success, it returns a positive number of the number of bytes
- * it copied.
- *
- * On failure it returns -EBUSY if all of the content in the
- * sequence has been already read, which includes nothing in the
- * sequence (@s->len == @s->readpos).
- *
- * Returns -EFAULT if the copy to userspace fails.
- */
-int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
-{
- int len;
- int ret;
-
- if (!cnt)
- return 0;
-
- if (s->len <= s->readpos)
- return -EBUSY;
-
- len = s->len - s->readpos;
- if (cnt > len)
- cnt = len;
- ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
- if (ret == cnt)
- return -EFAULT;
-
- cnt -= ret;
-
- s->readpos += cnt;
- return cnt;
-}
diff --git a/lib/Makefile b/lib/Makefile
index 7512dc978f18..a1aa1e81ed36 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -13,7 +13,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
proportions.o flex_proportions.o ratelimit.o show_mem.o \
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
- earlycpio.o
+ earlycpio.o seq_buf.o
obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
lib-$(CONFIG_MMU) += ioremap.o
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
new file mode 100644
index 000000000000..84b6377df827
--- /dev/null
+++ b/lib/seq_buf.c
@@ -0,0 +1,346 @@
+/*
+ * seq_buf.c
+ *
+ * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The seq_buf is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the seq_buf must be initialized with seq_buf_init().
+ * This will set up the counters within the descriptor. You can call
+ * seq_buf_init() more than once to reset the seq_buf to start
+ * from scratch.
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/seq_buf.h>
+
+/**
+ * seq_buf_print_seq - move the contents of seq_buf into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the seq_buf descriptor that is the source.
+ *
+ * Returns zero on success, non zero otherwise
+ */
+int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
+{
+ unsigned int len = seq_buf_used(s);
+
+ return seq_write(m, s->buffer, len);
+}
+
+/**
+ * seq_buf_vprintf - sequence printing of information.
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ * @args: va_list of arguments from a printf() type function
+ *
+ * Writes a vnprintf() format into the sequencce buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
+{
+ int len;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
+ if (s->len + len <= s->size) {
+ s->len += len;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_printf - sequence printing of information
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ *
+ * Writes a printf() format into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = seq_buf_vprintf(s, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
+/**
+ * seq_buf_bitmask - write a bitmask array in its ASCII representation
+ * @s: seq_buf descriptor
+ * @maskp: points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits: The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ /*
+ * Note, because bitmap_scnprintf() only returns the number of bytes
+ * written and not the number that would be written, we use the last
+ * byte of the buffer to let us know if we overflowed. There's a small
+ * chance that the bitmap could have fit exactly inside the buffer, but
+ * it's not that critical if that does happen.
+ */
+ if (len > 1) {
+ ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
+ if (ret < len) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+#ifdef CONFIG_BINARY_PRINTF
+/**
+ * seq_buf_bprintf - Write the printf string from binary arguments
+ * @s: seq_buf descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ if (s->len + ret <= s->size) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+#endif /* CONFIG_BINARY_PRINTF */
+
+/**
+ * seq_buf_puts - sequence printing of simple string
+ * @s: seq_buf descriptor
+ * @str: simple string to record
+ *
+ * Copy a simple string into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_puts(struct seq_buf *s, const char *str)
+{
+ unsigned int len = strlen(str);
+
+ WARN_ON(s->size == 0);
+
+ if (s->len + len <= s->size) {
+ memcpy(s->buffer + s->len, str, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putc - sequence printing of simple character
+ * @s: seq_buf descriptor
+ * @c: simple character to record
+ *
+ * Copy a single character into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putc(struct seq_buf *s, unsigned char c)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + 1 <= s->size) {
+ s->buffer[s->len++] = c;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putmem - write raw data into the sequenc buffer
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + len <= s->size) {
+ memcpy(s->buffer + s->len, mem, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+#define MAX_MEMHEX_BYTES 8U
+#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
+
+/**
+ * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to seq_buf_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len)
+{
+ unsigned char hex[HEX_CHARS];
+ const unsigned char *data = mem;
+ unsigned int start_len;
+ int i, j;
+
+ WARN_ON(s->size == 0);
+
+ while (len) {
+ start_len = min(len, HEX_CHARS - 1);
+#ifdef __BIG_ENDIAN
+ for (i = 0, j = 0; i < start_len; i++) {
+#else
+ for (i = start_len-1, j = 0; i >= 0; i--) {
+#endif
+ hex[j++] = hex_asc_hi(data[i]);
+ hex[j++] = hex_asc_lo(data[i]);
+ }
+ if (WARN_ON_ONCE(j == 0 || j/2 > len))
+ break;
+
+ /* j increments twice per loop */
+ len -= j / 2;
+ hex[j++] = ' ';
+
+ seq_buf_putmem(s, hex, j);
+ if (seq_buf_has_overflowed(s))
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * seq_buf_path - copy a path into the sequence buffer
+ * @s: seq_buf descriptor
+ * @path: path to write into the sequence buffer.
+ * @esc: set of characters to escape in the output
+ *
+ * Write a path name into the sequence buffer.
+ *
+ * Returns the number of written bytes on success, -1 on overflow
+ */
+int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
+{
+ char *buf;
+ size_t size = seq_buf_get_buf(s, &buf);
+ int res = -1;
+
+ WARN_ON(s->size == 0);
+
+ if (size) {
+ char *p = d_path(path, buf, size);
+ if (!IS_ERR(p)) {
+ char *end = mangle_path(buf, p, esc);
+ if (end)
+ res = end - buf;
+ }
+ }
+ seq_buf_commit(s, res);
+
+ return res;
+}
+
+/**
+ * seq_buf_to_user - copy the squence buffer to user space
+ * @s: seq_buf descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequence (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
+{
+ int len;
+ int ret;
+
+ if (!cnt)
+ return 0;
+
+ if (s->len <= s->readpos)
+ return -EBUSY;
+
+ len = s->len - s->readpos;
+ if (cnt > len)
+ cnt = len;
+ ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+ if (ret == cnt)
+ return -EFAULT;
+
+ cnt -= ret;
+
+ s->readpos += cnt;
+ return cnt;
+}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 22/23 v4] printk: Add per_cpu printk func to allow printk to be diverted
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (20 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 21/23 v4] seq_buf: Move the seq_buf code to lib/ Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
2014-11-14 1:13 ` [RFC][PATCH 23/23 v4] x86/nmi: Perform a safe NMI stack trace on all CPUs Steven Rostedt
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek,
Paul E. McKenney
[-- Attachment #1: 0022-printk-Add-per_cpu-printk-func-to-allow-printk-to-be.patch --]
[-- Type: text/plain, Size: 3548 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Being able to divert printk to call another function besides the normal
logging is useful for such things like NMI handling. If some functions
are to be called from NMI that does printk() it is possible to lock up
the box if the nmi handler triggers when another printk is happening.
One example of this use is to perform a stack trace on all CPUs via NMI.
But if the NMI is to do the printk() it can cause the system to lock up.
By allowing the printk to be diverted to another function that can safely
record the printk output and then print it when it in a safe context
then NMIs will be safe to call these functions like show_regs().
Link: http://lkml.kernel.org/p/20140619213952.209176403@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/percpu.h | 3 +++
include/linux/printk.h | 2 ++
kernel/printk/printk.c | 38 +++++++++++++++++++++++++++++---------
3 files changed, 34 insertions(+), 9 deletions(-)
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index a3aa63e47637..ba2e85a0ff5b 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -134,4 +134,7 @@ extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
(typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
__alignof__(type))
+/* To avoid include hell, as printk can not declare this, we declare it here */
+DECLARE_PER_CPU(printk_func_t, printk_func);
+
#endif /* __LINUX_PERCPU_H */
diff --git a/include/linux/printk.h b/include/linux/printk.h
index d78125f73ac4..3bbd979d32fb 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -162,6 +162,8 @@ extern int kptr_restrict;
extern void wake_up_klogd(void);
+typedef int(*printk_func_t)(const char *fmt, va_list args);
+
void log_buf_kexec_setup(void);
void __init setup_log_buf(int early);
void dump_stack_set_arch_desc(const char *fmt, ...);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ced2b84b1cb7..f7b723f98cb9 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1807,6 +1807,30 @@ asmlinkage int printk_emit(int facility, int level,
}
EXPORT_SYMBOL(printk_emit);
+int vprintk_default(const char *fmt, va_list args)
+{
+ int r;
+
+#ifdef CONFIG_KGDB_KDB
+ if (unlikely(kdb_trap_printk)) {
+ r = vkdb_printf(fmt, args);
+ return r;
+ }
+#endif
+ r = vprintk_emit(0, -1, NULL, 0, fmt, args);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(vprintk_default);
+
+/*
+ * This allows printk to be diverted to another function per cpu.
+ * This is useful for calling printk functions from within NMI
+ * without worrying about race conditions that can lock up the
+ * box.
+ */
+DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default;
+
/**
* printk - print a kernel message
* @fmt: format string
@@ -1830,19 +1854,15 @@ EXPORT_SYMBOL(printk_emit);
*/
asmlinkage __visible int printk(const char *fmt, ...)
{
+ printk_func_t vprintk_func;
va_list args;
int r;
-#ifdef CONFIG_KGDB_KDB
- if (unlikely(kdb_trap_printk)) {
- va_start(args, fmt);
- r = vkdb_printf(fmt, args);
- va_end(args);
- return r;
- }
-#endif
va_start(args, fmt);
- r = vprintk_emit(0, -1, NULL, 0, fmt, args);
+ preempt_disable();
+ vprintk_func = this_cpu_read(printk_func);
+ r = vprintk_func(fmt, args);
+ preempt_enable();
va_end(args);
return r;
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread* [RFC][PATCH 23/23 v4] x86/nmi: Perform a safe NMI stack trace on all CPUs
2014-11-14 1:12 [RFC][PATCH 00/23 v4] trace-seq/seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
` (21 preceding siblings ...)
2014-11-14 1:13 ` [RFC][PATCH 22/23 v4] printk: Add per_cpu printk func to allow printk to be diverted Steven Rostedt
@ 2014-11-14 1:13 ` Steven Rostedt
22 siblings, 0 replies; 58+ messages in thread
From: Steven Rostedt @ 2014-11-14 1:13 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Andrew Morton, Jiri Kosina, Petr Mladek,
Paul E. McKenney
[-- Attachment #1: 0023-x86-nmi-Perform-a-safe-NMI-stack-trace-on-all-CPUs.patch --]
[-- Type: text/plain, Size: 5340 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
When trigger_all_cpu_backtrace() is called on x86, it will trigger an
NMI on each CPU and call show_regs(). But this can lead to a hard lock
up if the NMI comes in on another printk().
In order to avoid this, when the NMI triggers, it switches the printk
routine for that CPU to call a NMI safe printk function that records the
printk in a per_cpu seq_buf descriptor. After all NMIs have finished
recording its data, the seq_bufs are printed in a safe context.
Link: http://lkml.kernel.org/p/20140619213952.360076309@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86/kernel/apic/hw_nmi.c | 91 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 86 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 6a1e71bde323..c95c3e9ce196 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -18,6 +18,7 @@
#include <linux/nmi.h>
#include <linux/module.h>
#include <linux/delay.h>
+#include <linux/seq_buf.h>
#ifdef CONFIG_HARDLOCKUP_DETECTOR
u64 hw_nmi_get_sample_period(int watchdog_thresh)
@@ -29,14 +30,35 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh)
#ifdef arch_trigger_all_cpu_backtrace
/* For reliability, we're prepared to waste bits here. */
static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+static cpumask_var_t printtrace_mask;
+
+#define NMI_BUF_SIZE 4096
+
+struct nmi_seq_buf {
+ unsigned char buffer[NMI_BUF_SIZE];
+ struct seq_buf seq;
+};
+
+/* Safe printing in NMI context */
+static DEFINE_PER_CPU(struct nmi_seq_buf, nmi_print_seq);
/* "in progress" flag of arch_trigger_all_cpu_backtrace */
static unsigned long backtrace_flag;
+static void print_seq_line(struct nmi_seq_buf *s, int start, int end)
+{
+ const char *buf = s->buffer + start;
+
+ printk("%.*s", (end - start) + 1, buf);
+}
+
void arch_trigger_all_cpu_backtrace(bool include_self)
{
+ struct nmi_seq_buf *s;
+ int len;
+ int cpu;
int i;
- int cpu = get_cpu();
+ int this_cpu = get_cpu();
if (test_and_set_bit(0, &backtrace_flag)) {
/*
@@ -49,7 +71,17 @@ void arch_trigger_all_cpu_backtrace(bool include_self)
cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
if (!include_self)
- cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+ cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask));
+
+ cpumask_copy(printtrace_mask, to_cpumask(backtrace_mask));
+ /*
+ * Set up per_cpu seq_buf buffers that the NMIs running on the other
+ * CPUs will write to.
+ */
+ for_each_cpu(cpu, to_cpumask(backtrace_mask)) {
+ s = &per_cpu(nmi_print_seq, cpu);
+ seq_buf_init(&s->seq, s->buffer, NMI_BUF_SIZE);
+ }
if (!cpumask_empty(to_cpumask(backtrace_mask))) {
pr_info("sending NMI to %s CPUs:\n",
@@ -65,11 +97,58 @@ void arch_trigger_all_cpu_backtrace(bool include_self)
touch_softlockup_watchdog();
}
+ /*
+ * Now that all the NMIs have triggered, we can dump out their
+ * back traces safely to the console.
+ */
+ for_each_cpu(cpu, printtrace_mask) {
+ int last_i = 0;
+
+ s = &per_cpu(nmi_print_seq, cpu);
+ len = seq_buf_used(&s->seq);
+ if (!len)
+ continue;
+
+ /* Print line by line. */
+ for (i = 0; i < len; i++) {
+ if (s->buffer[i] == '\n') {
+ print_seq_line(s, last_i, i);
+ last_i = i + 1;
+ }
+ }
+ /* Check if there was a partial line. */
+ if (last_i < len) {
+ print_seq_line(s, last_i, len - 1);
+ pr_cont("\n");
+ }
+ }
+
clear_bit(0, &backtrace_flag);
smp_mb__after_atomic();
put_cpu();
}
+/*
+ * It is not safe to call printk() directly from NMI handlers.
+ * It may be fine if the NMI detected a lock up and we have no choice
+ * but to do so, but doing a NMI on all other CPUs to get a back trace
+ * can be done with a sysrq-l. We don't want that to lock up, which
+ * can happen if the NMI interrupts a printk in progress.
+ *
+ * Instead, we redirect the vprintk() to this nmi_vprintk() that writes
+ * the content into a per cpu seq_buf buffer. Then when the NMIs are
+ * all done, we can safely dump the contents of the seq_buf to a printk()
+ * from a non NMI context.
+ */
+static int nmi_vprintk(const char *fmt, va_list args)
+{
+ struct nmi_seq_buf *s = this_cpu_ptr(&nmi_print_seq);
+ unsigned int len = seq_buf_used(&s->seq);
+
+ seq_buf_vprintf(&s->seq, fmt, args);
+ return seq_buf_used(&s->seq) - len;
+}
+
static int
arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
{
@@ -78,12 +157,14 @@ arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
cpu = smp_processor_id();
if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
- static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+ printk_func_t printk_func_save = this_cpu_read(printk_func);
- arch_spin_lock(&lock);
+ /* Replace printk to write into the NMI seq */
+ this_cpu_write(printk_func, nmi_vprintk);
printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
show_regs(regs);
- arch_spin_unlock(&lock);
+ this_cpu_write(printk_func, printk_func_save);
+
cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
return NMI_HANDLED;
}
--
2.1.1
^ permalink raw reply related [flat|nested] 58+ messages in thread